Not sure what ur skill level is but here's what worked for me. At white belt i had athletic ability and felt comfortable on top, I quickly developed a passing game only focusing on 2-3 passes and getting proficient at them. Then when I wanted to compete I started working on wrestling, simple single double legs. After some practice i was much better at getting on top than most bjj guys but I ended up fighting a few wrestlers in tournaments. One of them would have had a blue belt at any other school and when he got on top thats all she wrote. I ended up winning a few other tournaments and soon enough i got a blue. When i got my blue belt it was pretty much with no bottom game, although my top game was good enough to beat purple belts. I realized this and for my entire blue belt career sat to bottom every time i trained. Soon enough my guard was really strong and my closed guard was my best position. I think its important to study aspects of bjj in pieces, at least that works for me best. Stick to a few simple moves that have variations and learn all the variations. This way you learn one move that can b used in 10 different ways in 10 different scenarios. Watch the best guys at ur gym and drill what they drill simplified, do it every day for a year. Ask for details and then keep drilling, did I mention that you should drill? Also try what u drill when you're rolling, for some reason when i pull off a move while rolling for the first time it is cemented in my brain forever.