While impersonal gifts such as candy, gift cards or plants usually work for a friend's birthday, gifts for your best friend need a bit more thought. Since you likely know a lot about your best friend's interests and habits, it should be fairly easy to come up with a gift that she will love.
You and your best friend have likely experienced many good times together, and his birthday is a good time to reflect on some of the highlights of your friendship. Put together a photo album or scrapbook detailing the history of your friendship or a special trip you have taken together. If you don't want to put together a whole book, frame a favourite photo of the two of you together. If you have a memento from a special milestone or occasion, put it in a shadowbox or frame and give it to him as a birthday gift.
Gifts of Experience
Since you and your best friend enjoy spending time together, give a gift that involves the two of you making new memories. Tickets to a concert or play, for example, make for a good birthday gift. If you want to spend less money, buy her a video or board game that you can play together. If you and your friend like to get together for a glass of wine, buy her a really nice bottle and make a date for you to cook her dinner and share the wine together.
Use your unique knowledge of your friend's preferences and background to put together a unique collection of items that reflects his tastes. Put together a special birthday gift hamper containing all of his favourite treats. Get a T-shirt printer to make a one-of-a-kind T-shirt that references a private joke the two of you share. Or hire an artist to draw a caricature or cartoon of your friend; if your friend has more refined tastes, opt for a professional oil portrait.
Review your history of gift-giving between yourself and your friend. If she has given you particularly generous gifts in the past, take that as a cue to buy her something really special in return. Since you are best friends, you may want to spend more money than you would on a less intimate friend and splurge on a piece of jewellery or a watch for her birthday this year. When buying opulent gifts for your friend, remember to compare the price level to what she has bought you in the past so you don't make her feel uncomfortable.