If the corner is sharp, then the skin will tear easily. Good drums have smoothly curved corners. If you don't like the sound, don't buy the drum. If it's a little high-pitched, ask if you can wet the skin a little. If you decide to invest in a higher-quality drum, here are some tips .
Beaters There are dozens of varieties of beater, differing in length, weight, shape, and balance.
I found it helpful to start with a very heavy stick with a large lump in the center. The central bump makes it easier to keep a grip on the beater, and the extra mass makes it easier to learn the basic techniques, especially the double-downstroke. As you improve, you may want to move to a lighter beater. You probably want to get several beaters of different weights and shapes. Experiment with them until you find one that's comfortable.