One of my favorite lettering tricks is to add text in one color, size or font. Let it dry. Once it's dry, I'll vary the text using a different color, size or font directly on top of it. I'll add text using my own hand most of the time. Sometimes I mix handwritten text with stencils, rubber stamps or rub-on letters. I love playing with my own handwriting when I go to add text!
Layering letters is a great technique if you think you've made a mistake. I just really like the way it looks. There are lots of lettering tricks out there if you keep your eyes open.