If you get a term sheet, make sure you understand it in depth. Valuation is not all, it is the mix of clauses together with the valuation that makes it a good – or not so good – deal for you.
It is highly recommendable that you get good legal advice, which usually you can get on a deferred basis: no payments until an investor comes on board. A suitable lawyer involved in many current transactions will have a good idea of the current deal terms and which negotiation leeway exists with investors. Ideally, the lawyer recently (i.e. within the last 6 months) negotiated with your intended investor.
If you are out there on your own or very early stage, you can also work with standardized documentation. These also provide a good education on the topic and prepares you what to expect.
Of course, you are welcome to discuss your situation and tactics with one of our mentors.