Steps to consider during planning of new project

Question

What are the points I must remember during the planning phase of the project to have a really firm foundation?

Thanks

Edit: I mean more specifically related to coding. (I don't mean the budgets etc etc).

For example: Where can we use generics,reflection or concepts in C#

Answer 1

During the planning phase you need to:

1. Define the problem your solving
2. Validate the problem actually exists
3. Define a solution with your customer (This is more of a starting point, I recommend constant user feedback into your lifecycle but you need to start somewhere)
4. Define the scope of the project, including features, cost / budget and time