There are some major skills you need to keep a relationship healthy. Two of such skills I know is the Ability or Maturity to Resolve Conflict without much friction, and Employing Diplomatic tactics in some situation; meaning you don't tell them that they suck, but you tell them they could get better. So, what skills do you know, please share with us.
I just do what comes naturally, too much time spent analysing your own relationship does not often work out for the better. My suggestion would be to engage in as much sexual activity you can manage with your wife/partner and keep things fun and moving by the possibility of adding others into your sexual games. Indeed sex is the normal driver of couples hitching-up together, so the more fun you can achieve from this simple activity will hold the marriage together and is far more exciting than obtaining "diplomatic tactic skills.
No matter what anybody says, sexual compatibility is so important....I don't think you can really change that...
I've read that the top predictor of a relationship staying together is the ability to communicate about things in the relationship that you are unhappy about in a non-aggressive, or even affectionate way.
I get emails from the Gottman Institute, they have a lot of tips based on scientic studies. The one you posted newbie-one is probably one they posted, I remember seeing the specifics of how to "argue" or something similar.
When was a young lad l learnt my skills from a much older women. Foreplay is important part of sex after being with her for a few months I was very confident. Soon after I had sex with this lovely Indian girl she told me afterwards it was amazing.
Find out what makes your partner happy and engage in the behavior that makes her / his happiness possible each and every day. ( unfortunately --I did not learn that until late in life. I wasn't an abuser--I just took my mates for granted.)
In 1964 I was a college freshman. One night in the college library I met a short, built, dark haired young woman. I had seen occasionally in high school and earlier. I called her up and we went on a date that included a number of exceptional kisses at the end. My Oh My! We were married two years later on 9-7- 1966. This morning after 57 years of a journey that went up hill and occasionally down hill, but always together, I leaned over and kissed that short, built, dark haired woman as she said “happy anniversary!”