If you really need to earn money fast and cannot find a full time job that pays enough then you may have to consider getting two part time jobs. Some people eve do a full time job during the day and then have a second job for evenings and weekends. This is not ideal as you can very quickly become tired but sometimes people feel that it is their only option.
When working two or more jobs there are some points to consider. Some employers will state in their terms of employment that you are not allowed to work for another company without their prior permission. Some companies only state that you cannot work for another company within the same industry or their competitors. You will also be taxed on both jobs, so for example if you earn £10,000 in job one then all of your tax allowance will be used up on that meaning you will be taxed on all of your earnings for job two. This will take the wage you expect to earn down substantially so it is worth checking what you will actually take home.