How to Pick a Good Thesis Problem

Is it well suited for you?

Is it personally interesting?

You need to find the topic sufficiently interesting that your enthusium will not lag throughout a year long effort

Are you qualified to do this project?

Are you sufficiently knowledgeable on the overall topic that you will be able to fully understand the project?
Do you have, or will you be able to learn any special skills required to carry it out?

Is it a significant problem?

Is it original?
Will it be of interest to others?
Will it make a ‘good story’?

The above are necessary conditions for selecting a project for you. But to be successful, the problem must also satisfy the sufficient conditions listed below.

Is it doable?

Are there sufficient data available or that can be gathered by you within your means and timeframe?
Do you have available the necessary facilities and ability to carry out the necessary analysis of the data?

To answer these questions you need to carefully think through the project at an early stage, and discuss all these topics with your mentor and advisor.