How do I start correctly in building database classes in c#?

Question

I am new in C# programming and in OOP. I need to dive into web applications for my company, and I need to do it fast and correct.

So even that I know ASP.NET MVC is the way to go, I want to start with some simple applications with ASP.NET Webforms and then advance to MVC logic.

Also regarding my db classes: I plan to create common database classes in order to be able to use them either from WinForms or ASP.NET applications.

I also know that the way to go is to learn about ORM and EF. BUT I also want to start from where I am feeling comfortable and that is the traditional ADO.NET way.

So about my Data Access Layer classes:

• Should I return my results in datasets or arraylists/lists?

• Should my methods do their own connect/disconnect from the db, or have separate methods and let the application maintain the connection?