1) Never stop getting to know your partner. Most of us aren't even done getting to know ourselves, so there's just no chance that you know every single thing about them no matter how long you've been together.2) Respect. This is a HUGE one, and unfortunately it gets ignored way too often. This is something that NEEDS to be applied to literally every single aspect of your relationship, even during the worst times. We all fight, but fighting in a respectful manner can make a big difference. Furthermore, no one is better than anyone else, so always treat your partner as an equal; and if you think you are better than them, don't let the door hit you on your way out :)
3) Express your sexual preferences. You wanna have sex more often? Then ask for it, or even better, initiate it. You like certain things a lot? Then say it. Also, returning the favour is always nice.
4) More on sex: make sure your sexual preferences MATCH. Some people don't need to have sex often, and it may not mean anything more than that. However, it may cause issues if you're a nympho. It's really important to find someone who is on the same sexual wavelength as you.
5) When you argue, emphasize how YOU feel. It's easy to point fingers, accuse, and insult. But give the whole "I feel _____ when you _____" formula a try. It should make your arguing more productive.
6) ALWAYS make your s/o feels special. Express that they make you happy. Tell them that they are the best thing that happened to you. Tell them that everyday you are grateful you met them; and don't forget to show them by always being caring and attentive to their needs. BTW notice how none of these things require money?
7) On the money topic...(this is a tricky one). My advice would mainly be to just not have any expectations. Both people should enjoy treating the other here and there, and at the end of the day the bills should be split according to incomes. One thing is for sure, there needs to be honest communication about this, and I would say the earlier, the better.
8) Don't let your past haunt you, and your partner. It's normal to have reservations at the beginning of any relationship and keeping your guard up. But not letting yourself be vulnerable after a few months will most likely just push the other person away. Learn from your past, and learn to embrace it. Don't make your partner pay for your ex's mistakes, and run the risk of sabotaging your relationship.
9) Accept and support all their hobbies and interests. You may not like that certain hobby yourself, but it's not your place to tell your partner what they can and can't do/like.
10) Make your s/o a top priority. Do not be too busy for them. If you have a stacked schedule, make time for them, and a lot of time. If you still can't manage to fit them in your life, stop wasting their time, and have fun being single for the rest of your life.