I am by no means an expert and there are a lot of folks out there hand-lettering much more nicely than I do. But, I do enjoy it. I like creating something that looks like it was handmade and not mass-produced. Signs are a dime a dozen nowadays, so I like the idea that something is crafted by hand, individually. And I do use stencils some times, but hand-lettering is so much more rewarding for me.
So, I like to practice hand-lettering in sketchbooks.
I most often use this paintbrush.
So, to recap--1) embrace hand-lettering and its imperfections, 2) practice, practice, practice, 3) chalk is the easiest way to make a rough draft of your sign, and 4)use a good paintbrush and a nice, smooth paint for your lettering.