Brain > Heart
Until you truly know a person by witnessing them in several different life situations and experiences, make sure that you use logic to assess the person you're falling in love with versus heart. I say this only because feelings make people illogical sometimes. The best thing to do is try to see the person in an unbiased view.
Do not rush
Unless you need a green card (lol), there should be no reason as to why you should be moving in with a person and rushing things. Take time to find out who you're moving in with, because once a few years pass by and you're common law, if a break up happens you'll be sharing your assets with that person regardless of how "shitty" they are.
Do'nt ignore red flags. Do not try to justify why someone has acted in a poor manner or has mistreated you. If you are starting to see the negative signs now, it won't be changing anytime soon. During the honeymoon stage is when the fun, and impressive gestures should be happening.
If he/she isn't communicating now, it is only going to hinder the relationship in the future. Simple. If you don't like something, say it. If you want something done, vocalize it. If the other person isn't telling you how they feel or what they need, passive aggressive tension will show up later on in the relationship.
What do you want
Do you know what you want? What is important to you? Whether it is financial stability, loyalty or even a good sense of humor- you have to walk in with some sort of guidelines as to what you want, and what you are not willing to part with.