Attending a Trainers' School would be the best way to learn more before setting out into the grass and searching for Pokemon. However, most Trainers' Schools are looking for at least one of the following Highers / A Levels: Battling, Power Of Friendship or Pokemon Psychology. Unfortunately most schools in the UK do not offer these specific courses.
Otherwise, befriend a wild Pokemon, then catch a decent team and practice in tall grass until you feel confident. See your local Professor to get a Pokedex before you set out - they may even offer you a starter pokemon that will allow you to skip the difficult first step of finding your first Pokemon. From there it's just a matter of working your way up the gyms, registering Pokemon in your dex, and becoming champion.