Do you mean the dexterity or do you feel you lack strength to press the strings down at the appropriate angle?

Dexterity will come with time and you just really have to keep trying. Sometimes I have to move my fingers into position with my right hand and just hold them there to get my fingers to stretch out. As for strength this comes with time as well but it's easier to build finger strength through exercises as opposed to dexterity. There are some grip strength devices available at your local guitar center or the like that can help with finger strength. You don't really need that though but things are available if you think it will help. Mostly you just have to keep doing it over and over.