The best way to convey that message is by giving something that a person will truly appreciate or use. It need not be anything expensive. Even simple gifts are appreciated so long as the thought is there. Before going shopping, you may want to ask around as to what the receipt may want. His or her friends or family are your best sources.
You can never go wrong with flowers. Most flower shops have delivery services, and you can also order on line. A more lasting floral gift is a flowering plant that can liven up an office cubicle. You may also send a care basket- a collection of items such as specialized toiletries and emergency kits. This is ideal for a single person. There are also online stores that can help you with this.
More practical people will appreciate gift certificates to their favorite stores. Perhaps you would like to try a more out of the box gift, like give that person an extraordinary experience on her birthday. Check out websites that offer various services from adventure packages to makeover projects.
Always remember that when giving a birthday gift, the rule is you should like the gift first. Ask yourself, if you would like to receive the same thing for your birthday. If you answer yes, then you're off to a good start. But if still no ideas come to mind, there are professional shoppers who can help you come up with a good gift idea.