I thought of a few more tips.

If you jump and look at a prop that scouts normally jump on to, a soldier might think that you're going to jump onto the prop and fire a rocket at it.

Get creative with your prop abusage, especially when you're fighting in indoor areas. One thing I like to do on granary 2nd is use the little clippings on the support beams you can jump on to get to upper.

Remember that soldiers wait until they know where you're about to land when you double jump before they fire a rocket. If you know a soldier only has a little bit of health left then jump before you take that last shot so that it tricks the soldier into waiting to fire his rocket.

At the start of mid demos will often shoot a sticky at one of the scouts so make sure to look out for it when you get to mid. Losing half of your health at the start of mid really sucks because you're mostly likely going to get focus fired for an easy first pick and that will make ur stats look bad.