Hi Monte,
RE: Levels... Basically when we talk about our 'levels' we are referring to the amount of AED's in our blood. Normally (In the UK at least) people dont have blood tests done. People know that their levels are either NORMAL --> They have taken all meds on time, LOW --> They have missed a dose or are late taking one, or (Less common) HIGH --> They have taken a dose early or have taken a double dose by mistake. You can have bloodwork done for your levels and I guess it is a good idea to have it done regularly to make sure that your body hasnt suddenly started consuming your AED's like smarties but I have to confess, its not something I have ever done. (Perhaps its more of an American thing)
RE: Shakes... I am guessing you mean involuntary twitching every now and again (Some people have it more regularly). Some epileptics seem to get it and some people dont. I do but I only twitch once or twice a day. Some of it could be your epilepsy but at the same time, some of it could be a reaction to your meds which is why (As Anvil has already said) you should tell your doctor.
Hope this helps
Darren