Ten top tips to help you complete your self-assessment tax return

April 6, 2024

We're here to give you confidence and get that tax return out the way. No jargon, no crazy fees, and knowing what you need to pay.

We've assembled untied's top tips to make your tax filing journey plain sailing.

  1. Don’t be afraid of tax
  2. Get organised
  3. Know how you earn
  4. Work through each source
  5. Claim relevant expenses
  6. Think what’s different this year
  7. Keep evidence
  8. File
  9. Set aside money to pay your tax
  10. To do all this quicker and easier, use untied 😊

Don’t be afraid of tax

There’s lots of support out there and you will know most of what is needed already. If you are unsure about anything, it’s important to seek advice when completing your return to clarify any areas of doubt and to ensure that your submitted return is complete and correct.

untied has a support section on our site, and HMRC has some excellent resources.

Get organised

This will help you relax by filing your tax return early without any deadline stress. If you’re already using untied, this is not going to be a problem for you. However if you’re going to be filing online, you’ll need a whole host of information and paperwork, including:

It’s best to keep accurate records of income and what you've claimed as business expenses throughout the tax year so that you’re ready to go, and make sure you declare everything.

You will also find it helpful to use untied's tax return checklist.

Know how you earn

Writing a simple list of where your money comes from - this could be money you earn through an employer, through self-employment, rental income, bank or building society interest or any recent dividend payments.

Work through each source one at a time

You’ll find that you’ve got more information than you realise. If you’re self-employed or renting out property, your bank records – especially if connected through a product such as untied – will have a lot of the information

Claim relevant expenses

HMRC allows you to deduct the costs of certain purchases that are necessary to run your business. This includes mileage if you’re self-employed or renting out property (don’t double claim fuel / car costs) and a working from home share. These costs can be deducted from your profit, and by doing so, will reduce the amount of tax you'll owe. In general, unless something you buy for your business is a capital asset – like a car (which you claim for under different rules) - you can deduct its full cost when working out your taxable profits.

Allowable expenses can include things like travel and accommodation expenses, office property and equipment, legal and financial costs, marketing, entertainment, subscriptions and training. More here.

Keep evidence

It’s good to use the principle of “what will help explain this transaction?” This can be a mix of paper and electronic. You don’t need to send this to HMRC, but need to have it to hand in case there are any queries.


If you think you’re ready, get your tax return filed. Obviously, you can do your tax return as early as 6 April but if you are not one of those keen beans, we urge you not to wait until 31 January to file your return. If you find you’ve missed something you can send an amendment later. If you do end up doing it at the last minute you are more likely to make mistakes or miss out vital information. Plus if you need to get in touch with HMRC for any reason, it is more difficult the nearer the deadline you are.

Set aside money to pay your tax

You can file now and pay later. Once you’ve submitted your return, HMRC will tell you what to pay. You can manage any surprises with your tax bill by budgeting in advance for what you anticipate your tax bill will be and getting ahead if you need to make any payments on account. Set aside a portion of your income every month for paying tax and National Insurance contributions. The payment deadline is also January.

To do all this quicker and easier, use untied 😊

We would say this, wouldn’t we? But it’s true! We developed untied to specifically help the self-employed and property landlords to get on top of their taxes. untied is the only end to end app that enables users to link their bank accounts – so you don’t forget any business expenditure or income. It makes tax sense of their transactions, files directly to HMRC and allows you to pay your tax bill. We save you time and money. That’s got to be a good thing, right? Take a look here.