Drills are where the rubber hits the road, where a jiu jitsu technique (or concept) you've been working on slowly starts to become something you can hit during live rolling. Here are a couple of effective lapel guard drills you can do in order to improve specific skill sets.
Lapel Guard Directional Drill
Starting with their lapel in both hands and your feet on their hips, practice "catching" the lapel with your feet each time you pass by it, in order to help you stay connected. You can gradually figure out how to keep someone in your guard this way, and if they get too far away, you can pull them back in using the same lapel.
Note that you can push to either side, or you can push up with your feet, depending on the situation.
Grip switch drill
Start with their lapel in your right hand, and pass lapel over your right ankle, legs, establishing Ringworm Guard.
From here, establish Worm Guard with a grip switch, and then back to ringworm guard, and so forth, round-tripping frequently. The idea is to become gradually better at the transitions between the positions.