HMRC has produced toolkits to provide guidance on areas of error frequently seen in tax returns. These toolkits set out the steps that you can take to reduce those errors. Here the ICAEW Tax Faculty lists the available toolkits and provide further information and guidance about how they may be used.
All toolkits can be found through links on the HMRC web page. HMRC updates the toolkits regularly (annually in most cases).
List of available toolkits