How can I build up my credit score this year?

If you are able to do it, try doing micropayments. I did this for a few cards and my scores went up pretty fast. The idea is to pay more frequently, so instead of once a month, 2 to 4 times a month.

Pay as much as you can as often as you can. Focus on cards that are closer to being paid off. If you have to, let larger bills slide for a few months. most credit cards don't have direct penalty charges like bank cards do.

Keep your payments steady. Don't skip out on any of your payments and be sure to pay them on time. If you can afford to make two payments a month, do so but try to focus it on two halfs, so the first week of the month and then the last week of the month.

I have been making steady payments on time for 6 months and my score has not improved so apparently this is not the case for everyone. I am trying to figure out what I am doing wrong.

Always pay your monthly bills on time. You can consider opening a new credit source be it in the form of a credit card, cell phone contract, or automotive lease. These will boost your scores.