I'll second the advice in Lanya's link about LEEWS.
I also found LEEWS to be a helpful place to start. You have to take the time to do the program, all of the exercises. It made me feel like a had a strategy for my midterms amd I was definately calm in the tests themselves because I had a plan. I wasn't just outlining madly.
My results at midterm were an A in Civ Pro, A- in Torts, C+ in Contracts, C+ in Property and a B in Crim. So clearly good results in 2 classes, not so good in others. But then I went on to fine tune my strategy for each class. Property was off because I just suck at future interests. The final was all essay. Contracts was off because the prof didn't like the way I organized the exam. That I could fix. Had an A- average on my finals which is law review at my school.
So I'd say that LEEWS can be a good place to start thinking about your exam strategy. Add to that good communication with your profs about their preferences (some will tell you what they want, some will keep nasty secrets like the fact that they hate IRAC with a passion, but they really want you to do exactly that only in narrative form) and I think you'd be in reasonable shape for midterms. LEEWS also helped me because I hate to formally brief, just doesn't help me. It was nice to hear of an alternative method.
But again, I must stress, you must do the program actively and use it as part of your plan. I had to develop my strategy from there. But it was a good jumping off point.