You have explained good tips here. I like to add more tips as mentioned below:
- Clean your working area to remove dust.
- Start sanding away using circular motions. You may have to sand corners and crevices by hand. The best finish is achieved by sanding the entire car back to bare metal with a perfectly smooth finish. Wipe the whole surface down with a clean rag and thinners to remove dust, and wait until residue from the thinners evaporates completely before continuing.
- Mask up areas you don't want to paint using masking tape and newspaper or plastic sheeting. Take the time to do this job well to avoid unsightly over-spray.