Macro photography operates at such a small scale that tiny preparation gaps — a shaky setup, the wrong depth of field, poor lighting — become large problems in the final image.
At close focusing distances, depth of field becomes razor-thin, which makes aperture choice one of the most important pre-shoot decisions in macro work rather than something to adjust on the fly. A stable base — a tripod, or at minimum careful handheld technique — matters more here than in most other genres, since even small movements are heavily magnified.
Lighting deserves particular attention: your own body or the lens itself can easily cast a shadow over a subject at macro distances, so having a diffuser or small flash positioned correctly is usually part of the setup, not an afterthought. If the subject is alive — an insect, for instance — a plan for working quickly and without disturbing it matters as much as any camera setting.
A short pre-shoot checklist — aperture and depth-of-field plan, stabilization, lighting setup, a plan for the subject itself — turns macro's usual trial-and-error into something far more repeatable.
A few things to plan for