How do you improve your BJJ/grappling? Practice, practice, practice. Okay...but it's not just practice, it's also WHAT you practice. So, in trying to improve your game, take an objective look at your jiujitsu and try to identify what the weakest part of your game is. A really good way to identify this is competition. Competing with a stranger who doesn't know anything about what you do will highlight your weak points. So, now your goal is to improve this area. Maybe it's sweeping, maybe opening the closed guard, maybe getting out of being side controlled...whatever it is...now your goal is to work on this as often as possible in training. When you are rolling, especially with someone of a lower belt and/or lower skill level, let yourself get into your worst position. You don't need to tell your partner what you are doing. Now practice using your techniques from that position. Ask different people you roll with, especially higher level guys, what they do in that position. You are working to improve that part of your game. Keep working on it...maybe you make it a goal to work on sweeping for the next two months. Now, you won't be doing it all the time because there are always going to be times where you don't have control over the positions you get. Just keep on working on your weakest position and then you will eventually notice that you have an even weaker position...you have now built up the weakest part of your game so that it is no longer the weakest part of your game! And now you have a new weakest part of your game! Congratulations!!! Some people are reluctant to put themselves in vulnerable or weak positions. Okay, this is TRAINING. How will the weak parts of your game improve if you don't practice them and make them stronger? It can be scary putting yourself in these weak positions because you take a greater risk of "losing" or getting tapped. This is TRAINING.
So, after you have done this, take a good look at your game and identify your new weak area. Work on your new weak area for the next couple of months. Continue training and repeating this process and watch your game improve.