<p>Bob</p>
<p>You just have to practice more. And, you also have to stop calling your mistakes stupid. </p>
<p>All you have to do is keep things really organized with your homework and notes. Math is comprehensive. So, you have to consistently drill things. But what you might have to consistently drill, might be different from your classmates.</p>
<p>All I can tell you is that you should just keep a running list of any worked out problems which are hard for you and anything from the class notes which are hard for you. Keep that running list in the front of your binder or what have you and always look through it as well as add to it. Way before your fellow classmates normally do it, start breaking down that list of worked out homework problems and class notes onto index cards where you have the problem on one side and the answer on the other and then start testing yourself and drilling things over and over while consistently adding to it with some of the newer material you find hard. This is not the easiest way to go about things, but sometimes math is like that. </p>
<p>Also, if your tests are multiple choice, do not be scared to do some nice shortcuts. Some folks have already brought up plugging the answer into the original equation and all of that. There is also, for example, the matrix method for some things as well. </p>
<p>Just keep your head up and drill your own personal things you find hard and as long as you do that early enough, you will be alright.</p>