You don't need a degree in UK/EU but given how competitive any full time tagged course is, for many, a degree is necessary. (A tagged scheme is one where the airline has agreed to hire you after full time training but you still pay the exorbitant fee).
Ensure you have no limiting medical conditions. Eye sight, eg colour blindness, needs very strong prescription, cross eyed etc. Hearing, diabetes, kidney issues etc. Some conditions are hidden...
Other than that, play team sports if you can. Reason? Team work, team building. Also, handling pressure etc.
Get the best grades you can. Don't drink and drive (later) and avoid recreational pharmaceuticals.
Are you near a glider site? Wander over there for some cheap flying. You can't log it for your CPL but it's all great experience.