Only go to Uni if you're a specific career path in mind that requires a degree.
If you're not going to go to uni, then learn a trade, such as electrician or gas engineer, or even train driver - something where there are "barriers to entry" such as a professional regulator or specific training, so that you're not going to be competing against those who've not done the training etc., such as joiner or decorator where people tend not to care if they're experienced/qualified etc.
Ensure you get the best possible school qualification, i.e. GCSEs - particularly in Maths and English. They're "door openers" in later life should you wish to retrain or change careers (yes you can do them later in life (or equivalent), but it's harder and more costly) - best to do your best at school when it's cheap and you've got the time to study!
Learn about money, make sure you understand compound interest, credit card charges/interest, taxes. Control your spending, never get into too much debt and never default. A bad credit rating can have very long term consequences, limit your options and cost you more!
Broaden your horizons, friendship groups and contacts. There's a lot of truth in the saying "it's not what you know, it's who you know" at all levels of society. Knowing a "friend of a friend" can be a door opener in so many different ways, even getting a reliable tradesmen, someone to fix your car, first on the list when finding a flat to rent, etc - the saying doesn't just apply to rich people getting their mates a job in investment banking!