When they mess up, see to it that you have created such a trusting environment that they dare to admit to their wrongdoings. If they apologize, don't use their errors as leverage in future conflicts.
Be a role model, work hard, keep your finances in check, if you argue with your gf/wife/partner, keep it civilized.
Be generous but the let the kid know the value of money and the effort it takes to buy certain stuff.
Inspire them to take up a couple of sports, e.g. wrestling and a team sport like soccer or football. Team sport is a great way for improving social skills and your kid will also get good friends.
If he or she doesn't like school and think doing math is useless. Inform them about the practicality of having a degree or two. They might not know what they want to do but if they have good grades, they will have a lot more options to choose from. A degree is an entrance pass to more exciting jobs.