I'd recommend having a lawyer review all your contracts, vesting documents, etc initially and any future documents you are asked to sign.
Keep in mind not many startups are a home run or a rocket ship so usually it won't matter but you don't want to be on the outside looking in if it does take off.
If your board authorizes more shares, will my options - or my stock, if I have exercised my options - be diluted?
It might not be such a bad thing if your stock gets diluted, if by doing so you attract the RIGHT KIND of investment. Unfortunately, VCs aren't always clueful.
