How to store data securely to compliance with GDPR

I have successfully implemented  a GDPR compliance for my client recently and my main objective was how do I store data securely to compliance with GDPR. This was a new experience for me and I wanted to help as many as possible.

How do I deliver small projects or tasks?

Recently I have been asked that how do I deliver small projects or tasks? What is my approach to solve a problem/task? Well I said POC (Proof of Concept) because I think it is a one of cost effective way to tackle