>>12947286Depends on your country. In some countries attending and not being retarded is enough to qualify. In others its nearly impossible to even get to take the team selection test.
For the easier countries you should make sure to know the theory that is officially required but don't go further than that. Instead make sure to practice difficult but graspable problems regularly.
It's also important to always reflect on the problems you practiced whether you solved them or not. If you managed to solve them consider how practical your solution would have been in a contest setting, that is could you have come up AND written it down in a reasonable amount of time?
For problems you don't solve look at several solutions and think about how YOU could have found them yourself. That is consider where your train of thought lead you in the wrong direction and look for patterns you missed.
If possible practice with your peers and don't strain yourself too much. Also remember: only six people per country can qualify for IMO. Just because you study hard it doesn't mean you'll be good enough. Most people aren't. Don't get discouraged over it.