These things make all the difference:

Guitar Picks: Your choice of pick is extremely important. Light gauge picks will allow you to play faster, but sacrifice a bit of tone, while heavy picks give your sound a bit more clarity and presence. The most important thing here is that you have a pick that feels comfortable. Picks that you can't properly hold on to will do you no good.

Guitar Position: You'll see most classical guitarists playing with their guitar resting between their legs, with the instrument angled up about 30 degrees. This serves several purposes, and should be used by everybody, whether they're playing Bach or not:

1. When the fretboard is closer to your face, you bend your neck less, which makes extended practice sessions considerably more comfortable.
2. When your hands are relaxed, they generally lay with the palms facing towards your body. The further away from this position your turn your wrists, the more tense your arms become, and the more difficult it is to play your guitar. Chapman stick players probably have the most relaxed arms of all, because the chapman stick is played pointing vertically, which positions the hands in a very relaxed manner.
3. This position encourages better posture. It looks more professional, and is ultimately more comfortable. With your guitar over your right leg, it's quite easy to slouch over it. If we get really technical, we might even say that this will muffle some of the tone (this applies more specifically to acoustic guitars, of course).

Strap Length: I'm sure we can all agree that wearing your guitar down by your knees looks cool. However, the longer your strap gets, the more difficult it is to play accurately. A shorter strap will position your wrists in much more favorable positions to the fretboard.

Warming Up: No athlete can run a race without warming up first. Fingers, like legs, have (albiet, smaller) muscles, and will benefit immensely from a session of finger exercises and scales before you really begin practicing.

The Pinky: Yeah, the pinky sucks. It's small, weak at first, and awkward to control. Nobody likes learning to use their pinky, but it's essential if you want to learn to play well! The pinky will allow you to stretch further, play more diverse scales, and is essential for learning tricker songs. Thousands of guitarists before you learned to their pinkies, and you won't be able to play any of their material unless you learn to use yours as well.