First of all don't think it as a big task like it is board exam.You must have faced a lot of examination in your previous classes.Board exam is also like that , there is nothing to be tensed in it.
For study tips, always keep you uptodate .Study atleast 5 hr daily by following an exact timetable.That is the only thing you need to follow for getting good marks. Today itself ,make a timetable for everysubject and do it as properly such that you will complete every portion atleast 3 or 4 day before exam.There is nothing to be overtensed and don't study too much.Always find some time to relax like playing.That is also necessary to keep your mind fresh.If you are a morning person, then study more in morning and if you are not an early morning person then study more tough subject in which ever time you are comfort .That's all .. Just keep it simple. Hope this will help you Good luck.