Many guitarist are really amused by the bar that comes with the guitar, play with it for a while, and hardly ever use it again because they don't know how to really use it or stop using it because they can't really control the effect that well. Although some guitarists don't really like the weird tremolo effects, you can also get some very subtle beautiful sounds out of your tremolo bar, at least if you use it the right way. Well it must have something to do with people having no good control. Practicing tremolo is also something that is very difficult and certainly not an easy task. I pretty much consider it an advanced technique but if used subtle you can also start using it if you are not that advanced yet.
Lets start with a very basic exercise for learning to push down the bar exactly one whole note.
The first important thing you have to do is set the tremolo and grab it. Some guitarists actually grab it with their hand, but many others, including myself, rather hold on to the guitar pick and use the remaining three finger to control the tremolo bar. This works well with the straight screw-in Strat type arms. If the thread has become worn and loose so that the arm will not stay in a convenient place, unscrew the arm completely. Try to leave about 1 cm protruding from the hole so that you can remove it if necessary.