Limit the term of the United States President to a single 5 year term. Currently a first term president wastes the last 2 years of their 1st term focused on getting re-elected. And they spend their entire 1st term with vanilla politics because they don't want to risk not getting re-elected. So the country gets 4 years of politics geared toward a re-election effort. One term of five years offers ample time to make your mark if your not concerned about getting re-elected. A five year term staggers the presidency across the re-election of the House and Senate.
If you want to fix politics this is where it starts. If the truth be told many of these politicians want to be President for life. And it is often proposed that the laws be changed to extend the time a person can serve as president.