Tomorrow, I'm looking at being married for nine years, so I think I have some experience. We had both read, long before we got into an LTR, that most divorces stem from issues with money. And, having been in an LTR prior where that was exactly the situation--you learn.
*) Talk about finances. ALways keep the paperwork in a common place for anything that may be considered a joint venture.
*) Have a private account as well. I have my own credit card for my purchases and my own checking and my own savings. My paycheck goes to these locations first, then into:
*) a join account. We each pay a percentage, a predefined number, based on income (I tend to earn more than he does), needs and responsibilities.
*) Decide, together, if something is "joint" or "personal." For example, cable. I wanted it, (this was long before digital, ouch, that was painful to admit) and he didn't see a use for it. I started paying for that. However, when they started offering internet-we switched and then it became joint. We're a two car family as well, with separate jobs on opposite ends of town. Both cars are registered in both of our names, as is the insurance. However, I picked the truck, so I paid for that; he wanted an SUV, so he took that up. We both paid from the joint for registration and insurance.
Hope that makes sense.