Before you sign on the dotted line of an employment contract or offer letter, make sure that every point you worked so hard to negotiate for is documented. Candidates frequently tell me that they were promised something during the negotiation process, but because they didn't have a written record of the agreement, promises were not always honored by employers later on.
If an employer does not give you a formal offer letter, create your own letter to document all the points that were agreed upon including start date, job title, starting salary, time off, signing bonus, and any perks you have negotiated as part of your package. Ask the hiring manager or HR contact to sign your letter and keep it in your employment file. Be leary of employers who are reluctant to put each point of the offer in writing.