I took the AP Euro test three years ago (has it been that long? my goodness...) and must have done pretty well since I got a "5" and 6 credits at my university for it. Here are some things you might want to consider:
- It's more important to be aware of ongoing historical trends than actual names/dates themselves. For example, the AP Euro test won't ask you to name the successive governments of the French Revolution (Legislative Assembly, Convention, Directory, etc.) but it WILL want you to know what the ideas were behind the formation of revolutionary government. This is 500 years of European history we're talking about; no one could possibly remember all of the people and dates in which things happened. But you should be aware of why the events that were going on happened, e.g. what were the principle motivations for the Reformation? Why did Britain win the Seven Year's War against France? Explain the factors which contributed to the rise of fascism in the 1920s and 30s. You get the idea. That's the kind of thing that you'll see on essay questions, and if you can do the essays the multiple choice is easy. Of course specific details are always good and include them if you can, but it's better to grasp the larger concept than to know dates with no greater meaning behind them.
- A word on dates: you just about never need to know exact dates, but you do need to know the ORDER in which events occurred. So in other words you don't need to know that the revolt of the Netherlands began around 1570 and the Spanish Armada took place in 1588, but you do need to know that one came before the other and was a significant cause of the latter.
- If at all possible, make sure to take some practice tests before you take the test for real. Nothing prepares you better for an AP test than practicing with real tests from previous years. They are readily available for purchase if your school doesn't have them, although with only a week to go it might be hard to get hold of some copies. I had taken about 5 previous tests by the time I took the real one, and it was a piece of cake. Many of the multiple choice questions in particular are repeated almost verbatim on tests (there are only so many good questions, after all).
- Be sure to buget your time appropriately. There's nothing you can really say about the mutiple choice, just work through them as best you can and skip ones which you blank on to come back later. For the essays though, you have to be careful to allow an equal time for each of them. I highly suggest wearing a watch to take the tests, even better if it's one with a stopwatch built in. You get an hour for the multiple choice and 2 hours, 10 minutes for the essays; memorize those times if you haven't already.
- More on the essays: in order to do a good job, you need to block them out ahead of time. Spend 5 minutes on each essay listing facts which will support your thesis, then simply write them into a paper. For the document-based question (DBQ), you're going to want to go through all the documents first and jot down a quick sentence of what it means. Then go back to the question, block out the DBQ in the same way you would the essays, and write down which documents fit where to support the points you make. You don't have to use all the documents, but you do need to use most of them to get the highest score possible. Timewise, you want to spend your 130 minutes on the essay portion in this fashion:
5 minutes - planning first essay
30 minutes - writing first essay
5 minutes - planning second essay
30 minutes - writing second essay
10-15 minutes - planning DBQ
45-50 minutes - writing DBQ
If you aren't in the habit of planning out your essays ahead of time this can be difficult to get used to, but I assure you it saves time because you avoid blanking halfway through writing. It also does wonders for the organization of your essays, and the AP people will appreciate ANY structure to your essays (since most students aren't going to have much).
- And above all, don't panic! You're going to get tired at some point but you can't let that get you down. Just remember that I had to take an AP English Lit test in the morning and an AP Stat test in the afternoon of the same day when I was a senior (ouchie!) That was not my conception of fun.
I hope this was helpful; everyone prepares for tests differently, but I've found these methods to be useful. Speaking as someone who received a 5 on both AP history tests, a perfect score on the SAT2 US History test, and who has never received a grade lower than an A- on any history exam in college, I think I am in a good position to give advice.
Expect something on facsism/communism too, there's frequently an essay either on how they came about or asking you to compare their features. Essays on the Cold War and decolonialism are possible but less likely; the test tends to put much less of a focus on events that happened after WWII. Don't even bother looking at anything that happened after 1975; it won't be on there (maybe a multiple choice question, but never an essay). 
