You have already taken the first step, by realizing how important it is to be a good father, and then deciding you want to be that kind of father. As we look toward Father's Day this weekend in the United States, I pray many other fathers will decide to follow your example.
One of the most important things you can do for your children is to let them know you love them–clearly and often. Tell them you love them ... hug them ... spend time with them ... listen to them ... encourage them. They need to know they are important to you, and the best way to do this is to let them know you love them. That doesn't mean you never discipline them when they need it–but when you do, they'll know you're doing it not out of anger but out of love.
Then pay attention to your example. Children not only learn from what we say to them, but also from what we do. The Bible's advice to those who teach applies also to us as parents: "In everything set them an example by doing what is good" (Titus 2:7).
Finally, point your children to Christ and His will for their lives. More than ever, children today need solid moral and spiritual foundations–and you have a responsibility to help give these to them. Make sure of your own commitment to Christ, and then do all you can to put Him at the center of your family.