1. Before doing anything check to be sure that your wheel is square in the dropouts. The easiest way to do this is to stand the bike up on it's own two wheels, then open and close the axle quick release.

2. Linear pull brakes (It has to be Shimano to be a V-brake) have a little screw at the base of one or both brake arms. By turning that screw you can adjust the return spring tension. Fiddle with it until both brake arms move together.

3. Probably the random clunks you are hearing is the result of improperly adjusted shift cable tension. If that's the case, turning the barrel adjuster that's adjacent to the rear derailleur 1/4 turn CCW will usually fix it.