I struggle with form (or making decisions about form) a lot, so take this all with a pinch of salt…
Different moods “suggest” or “need” different forms. You could say different “sub genres” but I prefer “moods”. The mood suggests the form and the method of getting from one part of the form to another.
Hypnotic, trance-inducing techno, needs builds, slow changes, small variations. You can introduce big changes but you usually need to telegraph or foreshadow them with a long breakdown, or a slow build-up, or both.
“Ravey” moods benefit from bigger, more sudden changes, and for short variations around a common core.
“Driving”, forceful techno keeps the energy fairly constant but introduces new colours quite often, with occasional drops and builds to let your dancers catch a breath.
IDM’s more flexible, and tends to consciously avoid most the previous forms.
Minimal techno uses the elements from above to tell stories. Tech-house keeps the energy levels fairly controlled and consistent, with efficient breakdowns and softer drops.
Break your work down into:
strategies: the overall shape of the track (length, mood, the main ideas)
tactics: how you get from one section to another: big changes or small, breakdowns or bringing in/swapping elements
By all means just jam and record it. Going with “the vibe” will let you ride all the previous ideas intuitively. However, giving your music or that of others, a bit of thought about what it’s doing and how, whilst you’re not jamming, will help you in later jams.