Modeling

I have been struggling with trying to understand the basic concepts of modeling - i.e. entities, keys, etc. I have been creating AppleWorks databases since about 1993, and need to port it all to Filemaker for greater stability (and because AppleWorks won't work forever). If I have to, I'll create flat files, but would like to use more of Filemaker 8.5's capabilities, including web publishing, so I can access my databases if I need to while mobile. I want to keep it as simple as possible!! I have no inventory.

My business is essentially recruiting and consulting: providing staff for the wine industry. I have a client/prospect file (about 2000 records) (AppleWorks), and a similar file which contains the people who work for me (or could), about 1000 records so far. I have a third file (currently a spreadsheet) which contains all the projects I've done (200 so far). If the file can handle it, I could put all the projects in one table; or is it better to have one for each year?

I've been envisioning the structure as one table for clients/prospects; one table for staff; one table for projects. I think that invoices could be a view of the project table?

The financial aspect is on a project OR hourly basis, with project expenses passed onto clients with no markup. (My project fee is higher than what I pay staff; that's the only profit.)

I hope this all makes sense. I am stuck with not understanding the basic structure of relational databases, despite having done lots of reading, and trying to build this. Any help is appreciated!