Cabbage,
A good tip to remember with your solids also is the "Seam edge". When you create a sold to use, before you do anything, try to have that seam edge rotated out of the way of other operations. It's not a must, but in certain circumstances having 2 seam edges exactly graze along each other can cause problems. Like if you create a sphere and align some other cutting object directly on that sphere seam edge, then try to fillet that edge, you "could/may" experience poor results.

Again, just a good habit to develope when starting out.