I mean, I'm not that good, but from high school and the top players in my team, probably just watching chess videos, maybe playing through/analysing games, and otherwise just relaxing or going about your daily routine.
If you have a buddy then you can make him a sparring partner and bounce ideas/strategy off him
I have to prepare for an OTB tournament in last week of March, this is my first FIDE rated OTB tournament, and iam really confused what to prepare and what not to. When I start to prepare openings someone comes along and says openings are not that important in under 1600 tournament (I think I know first 5-6 moves of all the major openings), when I work on middle game something happens and then I start working on opening and endgame. So, I thought why not ask this question here, as there are enough experienced players here who can guide me how to prepare for a tournament.