I use a bug writer, they're really good. The magnetic case version is super handy too, means you can keep it in your pocket easily and retrieve it at any time.
You might want to have a read of the first chapter of 13 steps to mentalism if you haven't read the book already - The first chapter is all about swami writers in general, you'll learn about several different types of writer and also you'll learn how to use them and some routines.
Hope that helps!