We always have 'our time' at the end of the day. We curl up front to back and snuggle and make sure we didn't miss saying anything during the day.
Call each other just for the heck of it. At least a couple times a day.
If something really bothers your partner, work to change it. You shouldn't require someone to change for you, but you should be willing to change for each other.
If you don't like it when your partner does something, don't do it yourself.
Have a pet name for each other. Something unique that you both love.
Always say hello and goodbye, kisses included
Always be polite. It matters.
Never go to bed without a kiss, even when you're both exhausted and would rather shut up and go to bed mad than argue all night.
Never mention divorce during an arguement.
Never take off your wedding rings when angry.