"Get a lawyer that understands startups. It's important to find someone with experience. Not only can a good lawyer explain what's going on with terms of your agreement, he/she can tell you if those terms are standard."
I would also add parties need their own lawyer. Founders, investors, and the company are all different entities with different interests. If you have multiple founders, it is wise for each to have separate counsel. I've seen too many instances where there is a law firm for the company/one founder, and a law firm for investors, but the other founders just kind of "go along" because they think their interests are aligned with founder #1, when that may or may not be the case.