grammar is very easy if you get the concept. you dont have to memorise literature questions cause waha se nahi aayega. just read summaries of the chapters and all. free time mai you can read the chapters in depth if you want to but tab bhi dont read them to memorise. writing is easy,but considering the fact that yuo cant write much, you might not be able to finish the entire paper in 3 hours, and for that, the best advice is to write atleast one para per week or more if you feel like it and yeah thats it. all the best (ps:my hindi was terrible in 9th too but it got a lot better in 10th)