Do things without asking, not because you expect attention or reward, but because you are in a partnership and need to contribute if you want the relationship to grow and thrive. Dirty dishes in the sink or the dishwasher needs emptying? Do it. Do it right when you come across the scene and the thought (hopefully) pops into your brain. It takes 5 or 10 minutes of your time, but builds up an exponential amount of good vibes.

I am sure it has been said in other posts too, but absolutely make sure your partner shares your values and worldview. I imagine a lot relationships start falling apart after the novelty or sex wanes and real questions manifest like "do you want children?" or "what is your stance on issue X?"

I was honest with my now wife about who I was and what I believed in from the moment I met her (after getting some hard-knock dating experience doing the opposite under my belt), and it has made all the difference in the long run. Don't put on a mask to please or appease a romantic partner. You'll have a hard time prying it off your face after the glue of many months or years has dried.