.You should disclose your income from each source in your self-assessment tax return. If you make a loss from your freelance work or as a partner you can offset those losses against your other income same tax year or previous tax year or you can carry them forward against future profits from the same businesses. Take a look here on losses.If you are making money from each source, then there isn't much you can do to avoid tax other than make pension contributions. There are other ways but they are really aimed at people with money they can afford to lose, eg Enterprise Investment Scheme, Seed EIS and Venture Capital Scheme.If your partnership or self-employed profits grow significantly, you might consider setting up limited companies. The companies will pay corporation tax at 20% on their profits but you will only pay tax on income you draw from the company in salary and/or dividends. At higher profit levels, there are tax and NIC savings to be made. Try putting some figures into the calculator here.I hope this helps but let me know if you have any further questions.