You have to be careful with the exhaust bump or you can break in to water passage. If it has a thermactor bump, it's easy to grind out. The bump for the rocker bolt can also be removed for better flow. You'll often break into the threaded area, but it's not hard to trim/grind the bolt/stud to length so it is flush with the roof wall, then seal the bolt/stud in the hole.
Careful streamlining of the valve guide helps and is fairly straight forward. Just leave enough for adequate support of the guide, especially if it's a street engine.
But in my opinion, anything beyond a careful and GENTLE smoothing of bowl edges should be left to experienced port guys with flow benches. If you try and remove material beyond breaking and rolling edges from the machine work, you'll likely hurt flow rather than help it. Every head design and engine is different, so generic porting articles often do more harm than good. Just a simple rolling of sharp bowl edges will help though,. As mentioned, the short side radius is very tricky and should be treated with kid gloves unless you have extensive experience or a guiding hand by somebody who is.
