You should be documenting your day, your week, your month, on a regular basis. Take a few minutes when you accomplish something and make a blog entry. This is a great way for you to keep track of what you’ve accomplished during the year, and be ready to talk about it in an interview, or in a performance review.
You don’t have to publically blog this. You can use Word, emacs, Live Writer, text files, whatever works, but, keep track of it. Read through it when you need it and summarize your accomplishments for the quarter or year. This is also something you consult every quarter when you touch your resume.
And when you get ready for that review, read Kendra Little’s post on asking for a raise.