Finishing things from Side Control can be tricky, especially when your opponent knows how to defend well. However, if you’re rolling in a Gi, then you’ll have more submission opportunities than it’d be the case otherwise.
For instance, you could use the opponent’s lapel for controlling them and tapping them out! Case in point: the Brabo Choke. Nick “Chewy” Albin demonstrates how to use this powerful lapel grip to overpower your opponents.

POWERFUL LAPEL GRIP & BRABO CHOKE FROM SIDE CONTROL 

First of all, you’re supposed to loosen up the opponent’s lapel on the opposite side of your Side Control. Then, feed it underneath their shoulder (you can lift them up a bit if necessary) to your other hand; beneath their neck. From here, utilize your shoulder pressure while simultaneously pulling the lapel towards yourself in order to make them feel as uncomfortable as possible.

Once there, you need to transition to Knee On Belly. Feed the lapel to your other hand again, and threaten the opponent with a Cross Choke. When they grab your hand to defend against it, simply grip their sleeve and pull them towards yourself. Slide down on your knee as you do so.
Once you have them on their side and their arm pulled all the way across to yourself, you’re going to trap this arm by driving your bodyweight through your shoulder on top of it. From here, just keep driving your shoulder as you pull on the lapel with your other hand; flexing your thumb down and scooping their head up in order to minimize space… And you’ll get the tap!

Watch Chewy demonstrate this lapel grip and Brabo Choke setup on the video below: