1. USE YOUR LIBRARY. The number of people I've met who can't find a book in the stacks is astounding. Your library will probably also have a ssearch engine for all the online databases it has access to.

2. Get a citation program. I use Zotero: it has a standalone program that works as a library/database for recording your sources, a browser plugin for automatically adding sourcea from pages like JStor, and a Word plugin that generates and updates all your citations, footnotes, and bibliographies.

3. Don't be afraid to ask faculty for things. Most people love to be asked about there particular area of expertise, and they'll be able to list authora and sources of value.

Cite everything, and I mean everything. Even in your own personal notes on your computer or written down, make a note of the book/article that you got the information from and the page. This will save you so much trouble when it comes to writing the paper. This is especially important with a History paper. Everything needs to have a source, and you will lose serious marks if you don't cite enough.

Avoid absolutes and broad sweeping generalisations. You don't want to give your professor ANY chance to write "but what about... etc" as a criticism. Don't, for instance, say "Communist countries were worse than democratic countries in the 20th century." That sentence has zero value. (And your professor will tear major holes in that argument).

Instead, allow for exceptions and explain your thoughts (with citations!). You might say instead that "many communist states arguably had worse human rights records than most democratic countries in the 20th century. For instance..." Here, you're covering yourself in case the professor has an example that you haven't considered - but make sure to back up everything you argue with solid evidence and sources!

I could go on and on, but just be careful to cite, don't make generalisations and do as much research as possible! Good luck!

What's already been said about citation and library use etc is good advice. I'd add that if you're making an argument for X, don't forget to consider all the arguments against X too - and address them in your argument.

Other than that, always read widely when researching asssignments. Don't just rely on a couple of books and a journal article. My rule of thumb when I was a student was for every 200 words long the assignment was expected to be, I should have at least 1 unique bibliography entry. So a 3000 word assignment had minimum 15 bibliographic entries. Minimum. That's to make sure you've got everything backed up appropriately, from a suitable range of different sources. If you're given a reading list, it might have five or six entries on. Start with them, but make sure you read more than that. Look for sources by looking at what the books and articles you're reading cite, or by searching for key words in your library catalogue and on Jstor. Look at the titles shelved near your sources in the library too - sometimes they prove useful.

If you are having trouble figuring out what to write, just start! Often times Ill have trouble trying to design an articulate introduction, or find a good place to start my writing session. They key is not to get hung up, not to let yourself fall into a bad case of writer's block. Rather, just start typing what youve been thinking about concerning the assignment. Even if its just a shity stream of consciousness, it gets your fingers moving and your brain working. Often times just organizing your thoughts into actual prose can help clarify exactly what you think about a topic, so dont be afraid to just start writing and worry about writing something good later!

If you're going to do several or these or something like a thesis, you may find it worthwhile learning to use something like Scrivener, which is intended to support writing long documents by forming a repository for notes, scanned papers and so on. It's worth spending half an hour looking at what it does, at least. If you are on Windows, Microsoft OneNote is also good, but less oriented towards supporting the writing process. One of the things I like about OneNote is that you can "print" a document (perhaps PDF scan) so that it forms a note in OneNote, send it to the background, then write notes over the top of it. It helps me a lot when I'm going through big technical documents. It will also do character recognition in scanned images, which means that you can search the documents you have scanned.

One tip for writing: be aware that your supervisor keeps a fully-charged cattle-prod in his desk in case you are unwise enough to use the word "obviously".

If possible, pick a topic you are interested in! Doing the research and writing for a paper of anything more than a few pages is much more engaging when you have a topic you can really dive into.

Cite your sources, every single one of them! It helped me to have a separate page for each book/journal article with all of the citation information at the top with my notes in bullet points for each page underneath. If you use a direct quote, absolutely remember to use quotation marks in your notes so that you do not forget when you write the paper.

I don't see where anyone else has said this, but I also remember many of my history professors wanting us to write in active voice rather than passive voice. You only have to write one 25 page paper, but your professor has to read many. Using active voice will make your writing more interesting.