If you are looking to make a will then a solicitor will be able to advise you and create one for you. Wills aren't just for people who are ill or old, everyone should make a will, particularly if you have dependants as a will ensures that your wishes are followed in the event of your death.
If you are getting divorced you will need to consult a solicitor. A solicitor will be able to advise you on the best course of action to take, the procedures that need to be followed and your entitlements.
If you are moving home or looking to buy property you will need to consult a conveyance solicitor. They are experts in property law and will ensure that your purchase and move are conducted correctly.
If you have been involved in an accident that wasn't your fault then you could consult a personal injury solicitor. They will be able to advise you whether your claim is valid and whether you are entitled to compensation. A lot of injury lawyers operate a "no win no fee" policy so you will only be charged if you win the case and receive compensation.
If you have an idea or an invention that you would like to market then it is advisable to have it patented to ensure that it cannot be duplicated by anyone else. It may be worth consulting a solicitor for advice on the best ways to do this.