Make sure you purchase a vinyl compatible with the fabric you want to use. Some vinyls are only for cotton, others work best on spandex.
Choose bold, easy to read fonts when adding letters to your design. Consider how much room you will have on the fabric you are transferring onto. For example, if your design is for a baseball hat, you might want to keep it simple, and not add too much information in it.
If you’re using words, make sure the letters are backwards, for example, “love” should read as “evol” in your design Similarly, make sure individual letters are backwards.
Take breaks to make sure you are cutting all the way through the first layer, but not cutting through the entire vinyl. You can also use a paper puncher or a die-cut machine to make fast shapes.