Find a CAD package: there are a lot of low-cost or free options out there on the market for PCB design. Things to consider when choosing a package:
1.Community support: are there a lot of people using the package? The more people using it, the more likely you are to find ready-made libraries with the parts you need.
Ease-of-use: if it’s painful to use it, you won’t.
Capability: some programs place limitations on your design- number of layers, number of components, size of board, etc. Most of them allow you to pay for a license to upgrade their capability.
Portability: some free programs do not allow you to export or convert your designs, locking you in to one supplier only. Maybe that’s a fair price to pay for convenience and price, maybe not.
2.Look at other people’s layouts to see what they have done. Open Source Hardware makes this easier than ever.
3.Practice, practice, practice.
4.Maintain low expectations. Your first board design will have lots of problems. Your 20th board design will have fewer, but will still have some. You’ll never get rid of them all.
5.Schematics are important. Trying to design a board without a good schematic in place first is an exercise in futility.
Finally, a few words on the utility of designing your own circuit boards. If you plan on making more than one or two of a given project, the payback on designing a board is pretty good- point-to-point wiring circuits on a protoboard is a hassle, and they tend to be less robust than purpose-designed boards. It also allows you to sell your design if it turns out to be popular.