You are talking about learning database design; this is refreshing and believe me when I say I like your approach -too many people are already doing stuff they have no clue about.
SQL Server is just one of a bunch of RDBMS therefore think about relational database design instead of SQL Server design.
I would say there are three areas you want to get in touch, just Google the words and you are going to find lots of free public domain documents in the net.
1- Relational Theory -Relational Model.
2- Data Modeling -Entity/Relationship modeling.
3- Data Normalization -You want to stop at the 3NF.
Good luck and please don't hesitate in posting any doubts you may have.
Pablo (Paul) Berzukov
Author of Understanding Database Administration
available at Amazon and other bookstores.Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.