How can one get relief on their income tax?

In the UK the HM Revenue & Customers website gives clear instructions how to obtain the various income tax allowances and reliefs either through a personal tax code or through a tax return. Generally speaking, the main allowance is your Personal Allowance which is the amount you are allowed to earn annually without paying income tax. Further tax reliefs can then be added for business related expenses. An accountant will be able to advise further.