Long term property calculations

[Burton Dines]

I have recently graduated from college and I am eager to immerse myself into the world of real estate properties. I have begun a project already with flipping a duplex, and I have learned a lot from everything that has happened so far. But I would like to be able to calculate things a little better in order to have a long term view on my progress and where I want to be. So are there any websites or books that people would recommend that helped them out for preparing and being able to establish a goal on a timeline? I think it's important to have a pace at which projects have to be occurring to keep on track, but let me know what your experience has helped you or what you found to be important.