I would start by working on your takedown defense. My philosphy for having trouble in bad positions is....dont let yourself get into a bad position! But the most important thing is creating space between you and your opponent. post your inside arm off his knee closest to your knee and shrimp away. from there its just a dog fight to regain guard/half guard.
If some one knows what there doing, and has a good side control. your going to have trouble getting away. I roll with real good purples and browns....so there half guard is beast, and your pretty ****** once your there, or it turns into a stale mate. like i said before..the philosophy for not getting in bad positions.
i try and bait people into a mount or knee on belly if the side control turns into a stalemate. then catch the re-guard. on there way to mount.
thats my style folks