Fist of all, I have to observe that fragrance gifting seems to be a procedure that is more or less loaded depending on culture and upbringing: Certain cultures apply highly individualistic attributes and sexualised messages to perfumes in general (designating perfume as an intimate gift or one which is an innuendo to more personal associations). To them, sometimes fragrance gifting from outside the tightest circle of family and/or lovers is suggestive in a manner too close for comfort. Others ~notably Southern Mediterranean people~, inspired by the wide use of Eaux de Cologne as a refreshing pick-me up with no attraction connotations whatsoever, indulge in fragrance gifting with less self-consiousness and it is indeed among the very traditional gestures, even among business associates! Additionally, highly urbanised terrains and younger ages allow for a bottle of fragrance to be seen more like a fashion accesory than a luxury "treasure" to be savoured on special occassions. Therefore, bear those factors in mind when considering to whom you're offering a gift of perfume or how you feel about this yourself (although I am assuming if you have made it here and thus far, you're not antithetical to the idea of presenting someone with a festively wrapped bottle of perfume!)
The first rule of successful fragrance gifting should be that you choose something that is according to the recipient's tastes and needs. Similar to how you wouldn't gift a socialite with a pair of galoches (where would she wear them to?), you don't want to overwhelm a young neophyte with something terribly complicated and meaningful that would feel out of place, yet without resorting to something that is a condescending cliché either. Going through very broad generalisations, it seems that younger women are rather averse to perfumey, face-powdery or floral fragrances as a rule (with the exception of tropical tiare and gardenia fragrances, it seems), prefering more culinary notes of vanilla, almond, tea and the like, or more abstract compositions that smell "out of the shower"/"clean" (those are usually combinations of various musks with synthetic florals or aldehydes). Younger men seem to be wanting to "blend in" (standing out takes either consious effort or the maturing of age), so a quick look through Sephora's best-seller list might provide some pointers to the general direction if not specific scents ~because you wouldn't want to buy what everyone else is buying! Never mind that several fragrances smell so similar to each other anyway.
So how do you go about it? A little investigation into what the recipient is actually enjoying right now is highly recommended. This can come through casual chit-chat (and if you paid attention all along in the past you should be able to at least pinpoint some favorite smells which might serve as a little steering help), through direct asking of what they're currently wearing or through observation of what they do have in their homes on the dresser or the bathroom shelf. If the latter is more silently conductive, pay attention that some bottles might have pride of place simply due to their decorative value, their prestige or simply because they were gifts by beloved people, yet they remain mostly unused (you don't want to repeat that mistake, do you?). Try to determine which of those fragrances get some actual use. If you can, do a comparative test with testers at the store, so you can pinpoint if you have actually smelled them wearing them. Who knows, you might find some little gems for yourself too, in the process!
If your direct question provides a direct answer à la "I am wearing Chanel No.5", there is the pressing tempetation to capitulate and buy just that. Try to resist acting upon it in the literal sense of buying another bottle of that fragrance. Replenishing a diminished stash might devalue the fragrance experience somewhat by unconsiously comparing it to refilling the fridge with milk. It doesn't make for the mingle of joyful surprise and guaranteed satisfaction that a successful gift entails. One lovely idea of bypassing this obstacle might be to buy some of the ancillary products in the same line of the fragrance: Often women -and men- are reluctant to buy those themselves, as they see them as an indulgence that is harder to justify, especially in times of financial recession (those body lotions, fragrant shower gels and shaving foams are more expensive than the more generic products for the same use). This solves two problems: it makes for a gift that can't go wrong smell-wise and it offers a little element of surprise combined!
Another idea, a little more elaborate but not too difficult, might be to search for something along the same lines as the scent of established "like": Belonging to the same olfactory family, encompassing similar "notes", or generally being a comparable style. To get help in this more sophisticated task, you can get help at the counter, but perhaps more effectively you can research a bit yourself online. Fragrantica and Osmoz are databases which describe the olfactory families (citrus, floral, oriental, woody, aldehydic, chypre, fougère) and classify many popular fragrances in them, so you have a little steering help. If, in the meantime, you're unsure what those chypres or aldehydes you're stumbling upon are and how they smell our articles on Perfume Shrine might be of help. (just click on the links and scroll!)
Michael Edwards of the Fragrance Foundation comes to the rescure too. His incredible database Fragrances of the World for feminine and masculine fragrances respectively, allows you to search for the fragrance you want to compare by its initial (how much simpler can you get!) and then shows you similar fragrances to it. It contains mainstream brands, classic fragrances, niche perfumes, as well as drugstore ones and discontinued scents which might have been otherwise obscure to decode. Very handy! Basenotes is another huge database of fragrances which lists fragrance "notes": you can search the desired fragrance of choice and compare and contrast notes of others; or better yet run them through their system by typing the ones you're interested in, in the appropriate box, separated by a comma (say: tobacco, hay, leather) ~five seconds later they will present you with several choices to choose from, masculine or feminine, whatever you prefer. For instance, these are the choices I got by randomly typing orange blossom, rose, tuberose, amber: A Demi-mot by Galimard, Trussardi Action Donna, Darling II by Fabergé, Magical Romance by Anna Sui, New York Nights by Girard, Razala by Ayala Moriel and Spellbound by Estée Lauder. You can do the same thing on the Fragrantica site as well.
Sometimes, among perfume afficionados, there is the seemingly practical advice of buying a sampler pack from Sephora to let the recipient of your gift choose what they like themselves, accompanied by a gift certificate to go on and buy that fragrance later on. Although this seems like a wonderful solution to the above dilemmas on shopping for fragrance for someone else, the recipient unless a hardcore perfumista/perfumisto is left with no goody bag to unwrap. A disappointing feeling, despite your better intentions... To avoid that, yet guarantee a successful purchase, you can buy whatever you have narrowed it down to and then ask the sales associate at the shop to include a sample vial of said fragrance inside the gift packaging, so that the giftee can sample the fragrance at the leisure of their home without ruining the packaging (this is especially important for the European market that does not accept returns of opened products, unless clearly defective). If you can, include a couple of samples of fragrances available in the same store, so that if the first is not as successful, maybe it will give them ideas and the return will be easy and enjoyable. It's generally a good idea to ask if returns are acceptable anyway and the specific terms of those returns -a simple return receipt, the time-frame in which it can be done etc.- and let the recipient know about them (they wouldn't ask you themselves out of politeness). This is especially important for men who often feel intimidated in department stores and boutiques and would rather let that pretty flacon gather dust than venture into that sea of unknown. If you suspect this is the case and it's someone close, offer to do it for them or accompany them and do some sniffing together. This is also a lovely bonding experience for couples (and eye-opening too, I might add).
Whatever you do remember another rule of thumb: Most people have not even heard of niche brands and no matter how much you want to introduce them to the delectable joys of Serge Lutens, Frédéric Malle or the newest wonder of Comme des Garcons for H&M, their products might smell weird to them and the brand recognisability will be nil (I realize that if you're reading Perfume Shrine you're probably beyond that, wearing what you like and perhaps even embracing the lure of the "being in the know" factor, but the average person is still swayed by what they perceive as "prestige" ~brands such as Chanel, Lancôme, Hermès, Guerlain, Christian Dior, Bulgari, Givenchy, Yves Saint Laurent et al have still a lot of covetability cachet in them).
Last but not least, some of the most popular and generally well-liked fragrances across the boards you're less likely to get wrong with (but there's no 100% guarantee!) include the following:
For women: Chanel Coco Mademoiselle, Prada Infusion d'Iris, Dolce & Gabbana Light Blue, Stella McCartney Stella, Burberry Brit, Christian Dior Hypnotic Poison, Philosophy Amazing Grace.
For men: Guerlain Vetiver, Gendarme by Gendarme, Armani Mania for men, Thierry Mugler Cologne, Gucci pour Homme, Gucci Envy pour homme, Prada Infusion d'Homme, Rochas Man, Paco Rabanne XS, Dior Eau Sauvage, Cerruti 1881, Terre d'Hermès.
Good luck shopping and remember, it's the thought that counts!
Related reading on Perfume Shrine: Christmas 08 Gift Ideas part 1
Pics from top via Flickr by 99elledge, DonnaGreyson and *an_drea.