Read the legitimate interest assessment (LIA) to make sure it meets your needs. Remember that if you have identified potential for a high risk to occur, you will need a compelling legitimate interest to rely on legitimate interest for the processing. You will also need to carry out a Data protection impact assessment.
Similarly, if individuals are likely to object to the data processing (eg because they find it intrusive), you will need a compelling legitimate interest to show that the interests in the processing outweigh the objections, in order to rely on legitimate interest for the processing.
Read Legitimate interest assessments for more information and remember that if you have any questions you can easily Ask a lawyer.