Startup Idea: Real Estate Client Management Software

Startup idea to develop a software for real estate professionals to organise and track their past clients' information conveniently, assisting in maintaining connections for future business opportunities. The software would offer solutions for data entry and identify common attributes to help categorize clients.

I am in the real estate industry I would like if I could use software to track down my past clients so that I could thank them for their business and hopefully gain new business. All the files of past transactions are in a mess in boxes. It would be very tedious for me to try to create an Access or Excel file with their information. I can't think of common attributes among them to even begin creating an Excel file. It would be very helpful if there was a way to organize them.