Common mistakes include missing the strict tribunal time limit, usually three months less one day from the dismissal, without starting ACAS Early Conciliation. People may also overlook eligibility rules, treat an ordinary grievance as a claim, resign without understanding constructive dismissal, or fail to keep key evidence such as contracts, emails and meeting notes. It is important to explain the facts clearly and show how you tried to resolve the issue, where appropriate. Rules can vary with the dismissal date and circumstances, so consider checking GOV.UK or speaking to an employment solicitor regulated by the SRA.