In 2017, charities failed to claim £600m in Gift Aid alone. You can claim Gift Aid on donations from UK tax payers and don’t forget the small donations scheme, which enables you to claim for small cash or contactless donations. The 2018 budget increased the smaller donations limit from £20 to £30.

In case you need it, here's an HMRC guide on how to complete you Gift Aid schedule. If you haven't claimed Gift Aid before, here's an article on how to do so.

Charities can claim VAT reliefs in areas, such as advertising, disability aids, construction, talking books, drugs and chemicals, rescue equipment, medicinal products, resuscitation models, medical and scientific equipment and even lifeboats. There are also exemptions for fuel and power, including the Climate Change Levy, and a refund scheme for museums and galleries offering free admission.

If you've missed out, you can make retrospective claims of up to 4 years. You'll also wish to be aware of the common pitfalls and, while you're at it, check that the VAT scheme you're using is the best one for you.

And make sure you've identified items that are VAT reduced or zero rated, or are exempt VAT, which includes fundraising events, or outside the scope of VAT, such as donations.

You can claim up to 80% business rate relief, if a property is used for charitable purposes. This is an additional business rates retail discount for charity retail shops.

You can claim up to £3000 in employment allowance, if you pay Class 1 National Insurance (most full time staff).

Land, buildings and shares, arts charities,importing free of duty and VAT, legacies, gifts to the nation, and payroll giving

Here are the guidelines on Corporation Tax allowances and reliefs and tax guidance for CICs. Individuals receive a 30% SITR tax break, when investing in an eligible organisation.

Companies pay a reduced rate of corporation tax on donations to charities. Additionally, sponsorship payments and the employee costs of secondments to charities and volunteering in work time, may be treated as business expenses.

For a whole range of guidance on charity tax, visit the Charity Tax Group.
If you haven’t yet registered with HMRC, here’s my guide on how to do so.
Tax is complex and I’m neither a tax adviser, nor accountant. This is simply an informal guide and I’ve no control over 3rd party articles or websites. Seek professional guidance, if you need it.