Preparing for Self Assessment: Our 5 Essential Tax Tips

Preparing for Self Assessment is essential if you earn income outside of PAYE – whether you’re self-employed, a landlord, a company director, or receive dividends or investment income – you’ll likely need to complete a Self Assessment tax return. Preparing for Self Assessment might seem like a once-a-year task, but the sooner you prepare, the easier it is to file accurately, avoid penalties, and stay in control of your finances.

Here are five practical tips to help you get organised and submit your Self Assessment with confidence for the 2024/25 tax year.

1. Get Your Records in Order Early

Accurate record-keeping is key to a stress-free Self Assessment. Start by pulling together everything you’ll need for the 2024/25 tax year – income records, invoices, bank statements, business expenses, pension contributions, dividend vouchers, and any rental income details.

Keeping your records organised (digitally or on paper) makes it easier to file and reduces the risk of errors. And remember: HMRC requires you to keep supporting documents for at least 22 months after the end of the tax year if you file your return on time. If you file late or are under enquiry, you may need to keep them for up to 5 years.

The earlier you start, the more time you’ll have to spot any gaps, and avoid a last-minute scramble in January.

2. Know Your Deadlines

Missing a Self Assessment deadline can lead to instant penalties – even if you owe no tax. Key dates to remember for the 2024/25 tax return (due in January 2026) include:

• 5 October 2025 – Deadline to register for Self Assessment if it’s your first time
• 31 October 2025 – Paper tax return deadline
• 31 January 2026 – Online filing and payment deadline

If your tax bill is over £1,000 and less than 80% of it was collected at source (e.g., through PAYE), you may also need to make Payments on Account (advance payments towards your next year’s bill) due on 31 January and 31 July.

Mark these dates now and aim to file well ahead of the deadline to avoid any last-minute issues.

3. Don’t Miss Out on Allowable Expenses

If you’re self-employed, a landlord, or have other qualifying income, you may be able to reduce your tax bill by claiming allowable expenses. These could include:

• Office and travel costs
• Professional fees
• Business-related subscriptions or training
• Maintenance and letting agent fees (for landlords)

Claiming what you’re entitled to – accurately and within HMRC’s rules – can make a big difference. Not sure what counts? That’s where expert advice can help.

4. File Your Return Early – Start Preparing for Self Assessment Now

Leaving your tax return until January can lead to stress, errors, and long HMRC wait times. Filing early gives you peace of mind, more time to budget for any tax owed, and a faster refund if you’re due one.

You don’t have to pay straight away – just having it submitted means you’re ahead of the game. It also gives you time to fix any issues without the pressure of a looming deadline.

5. Why Preparing for Self Assessment Early Pays Off

Self Assessment often means a lump-sum tax payment by 31 January – plus a possible advance towards next year’s bill. To avoid surprises, estimate your tax in advance and set money aside regularly.

If you think you’ll struggle to pay on time, HMRC may offer a payment plan, but you need to act early. Budgeting ahead helps you stay in control and avoids interest or late payment penalties.

Prepare Your Self Assessment Right the First Time

Preparing for Self Assessment doesn’t need to be stressful. With good records, early planning, and an understanding of what you can claim, you’ll be in a strong position to submit your return accurately and on time.

Need support filing your return accurately, or unsure what expenses you can claim? Our team can take the stress out of Self Assessment — whether it’s your first time or your tenth. Get in touch for expert, no-fuss advice.