What I like to do after the plan is just take it slow, I mean sort of like take a break. I know making a plan can be long and frustrating and sometimes boring, but just go through with it. You'll feel better after you complete the plan. You may feel like you don't want to do anything after that, because your so fed up with the work and time. So that's exactly what you should do. Take a day or two off, if you want to. Only when you're ready, will you continue to the third step.
Some people think that the second step is the best, just relaxing and doing nothing with your story and sometimes they never want it to end. But once in a while it's good not to take that long on this step. You may forget what you plan to do, regardless of whether you have a plan or not. You may never want to go back to the story, because you have a better story idea to do. So my advice to all you writers is: Don't take that long on this step, and, whatever you do, always go through with the story you planned to write. I mean- you might as well because you already made the plan and everything.
So go have fun. I'll see you later.