1. Good break-in
oil (Brad Penn or Joe Gibbs) is imperative.
2. Remove the inner spring or use a low ratio break-in rocker arm. If you have to pull a spring, you can either put some rope in the spark plug hole and use an on-head valve spring compressor, or you can use an air fitting. Either works about the same. There are several on-head spring compressors that work great. They just screw onto the rocker stud and allow you to pull down and compress the spring.
2. Have the timing and carb set so that it fires immediately.