This guy might be pushing his products, but he gives some very good advice as well. Worth a watch, some of his how to's. He also covers swirls and how to correct them.
https://www.youtube.com/channel/UCYsa8SOy3TkoxI5D17s1u-w
https://www.youtube.com/channel/UCYsa8SOy3TkoxI5D17s1u-w