Look closely at packaging. If you're in North America, Phillips is the most common for bulbs. They have packages marked 2700K, 5000K, and 6500K.
The colours are as follows: 2700- soft white (yellow hue), 5000- bright white (white hue, almost no colour), and 6500- day light (blue-ish hue, similar to fluorescent).
If you end up not being able to distinguish... ask an employee and they should be able to help