Translating SFX is a bit like jazz, once you get used to it. You find a rhythm and stick to it, and the more you play the better you get at improvising on that main beat while always finding ways to bring it back around to where you started. Also it helps to read lots of other comics and see what other translators are doing. Find things you like and make them your own.

Other than SFX, puns that are dependent on visual elements can go take a long walk off a short pier. The best translators are the ones who excel at creative writing and dumb jokes, because sometimes you have to take elements that make perfect sense together in Japanese but don't have a damn thing in common in English, and make something that binds them together AND is still funny.