After you receive your secret Santa, try to pay attention to little items your coworker often uses (especially if you're new in the workplace). That way, you can figure out a practical gift they'll actually appreciate.
Are they constantly touching up their makeup throughout the day? Religious about applying hand lotion after going to the bathroom? Get them a nice beauty gift set. If they're picky about certain products or brands gift them neutral staple items that fit the budget, like a sheer lip gloss or hand lotion.
If they drink several cups of coffee or tea per day, you know they'll appreciate a pretty decorative mug. Fill it with a few luxury tea bags or maybe a seasonal hot chocolate powder for bonus visual appeal.
Do they love showing you photos of their pets? Find some paraphernalia of said pet and you'll be golden. We don't mean that you have to snoop around for photos of the actual pet, but a generic product that features the species/breed. For example, a notebook, mug, or pendant.
If they're big on snacking, get them a few special Christmas treats. A nice box of chocolates or a collection of gourmet snacks will definitely go to use. If they prefer to cook themselves, give them a nice recipe book for fresh ideas.
The sporty one.
If they're big sports fans, try and find out their favorite team and pick up some swag (just visit the team's website). If they're gym addicts, give them an accessory like a quality water bottle.
Some people prefer staying in, especially during the winter, so set them up with the ingredients for a perfect cozy night. A nice candle, throw, cozy socks are all great ideas (if your budget allows for a combination of these items, go for it). If you know they have a bathtub, treat them to a bath bomb.
Whatever you do, steer clear of gift cards and definitely don't do your shopping at the discount store. Many nicer shops set up gifting areas with options available for all budgets. Pay a little extra attention and both parties will be having a very merry Christmas.