Seven Point Investment Checklist for Startup Investing
Before you invest ...
Nail down your angel investment thesis - answer the 10 Key Questions Before You Start Your Startup Investments.
Learn the basics and lingo of angel investing. Read Brad Feld's Venture Deals - this is an excellent read for first time investors and founders. Also check out the different angel investment program offered by 500 Startups in partnership with Stanford, Insead, Berkeley, etc)
Be mentally prepared and be realistic - Angel investing is extremely risky. Don't do this if you are looking for 1-2 years return. You may lose everything.
Be familiar with your startup environment - What are some of the most popular events and communities and who are the top angel investors, VCs and startup evangelists in your area? They could be the best source of referrals and startup network for you.
Ask for advice - there are plenty of great angel investors before you. Ask for their opinion, referral and advice
Be decisive and be a man/ woman of your words. Learn how to say no and articulate your thought process for why you decide not to invest. Startup founders would appreciate your honesty. The worst case would be committing to an investment and then backing out.. Word travels fast among startup founders...
Research the company. Use Crunchbase, AngelLists and CBInsights to research your target companies. You can easily find out their location, start date, founders' names, previous investors, total fund raised, etc