By having the facts on your side, proving negligence and proving damages.
Contact a lawyer, they could give you specific information based on the details of your case.
Contacting a specialist solicitor is certainly the best way to win a persona injury claim in the UK. But to win that claim your lawyer must show that someone was At Fault for your personal injury and that that fault or negligence actually caused your injury. For each type of personal injury you show fault in different ways. For example see the related link entitled "car accident claim" to see how to show fault in a RTA and see link entitled "accident at work claim" to see how to show negligence in a workplace accident claim.
The best thing you can do initially is to say as little as possible about your situation to anyone except law enforcement and your doctor until after you have consulted with a personal injury attorney. They will instruct you about what to say and to whom in order to protect your best chances of winning.