Give it time. I usually check my bottles every week to see what's going on. It might be drinkable at 3 weeks, but I'll never share with friends before 4. 5 weeks is usually perfect, in my opinion (depending on the beer, of course - some may need even more time).It'll be different depending on your brewing practices and your tastes. Most of my beer is ready to go within 3-4 weeks of brewday. That said, I'm not naturally carbbing.
Perhaps I should've clarified - I'm referring to time after bottling and assuming that priming was done with some sort of sugar.