Seller financed (probably) won't be reported to the credit bureaus and so won't impact your credit score at all.

Two, you'll have a much easier time obtaining a mortgage product if you have a track record of W2 income.In the meantime, continue implementing the strategies you mentioned: save religiously, build your credit, pay any existing debt owed, etc.

I am currently a student with some cash availbe and good credit score but no w2.

Nothing is foolproof of course, but having another investor in your market make a suggestion at least gets us on the right foot. 

Now, of course, you also get some principial paydown, but that may pale in comparison to an equity loss, if things do soften.

Quote from @Griffin Malcolm: Open an LLC and apply for a small business line of credit from Key Bank.

It is debt you are obligating yourself to and lenders and the federal government think of it that way.Missing a payment doesn't mess up your credit, but it does mess up your day when you get sued or prosecuted. 

And of course, getting good land for cheap makes the numbers work!   

If the applicant comes from the pool of people that I or my tenants know, I use real estate as a way to give back as many of my tenants will not qualify credit wise or may even have a criminal background or would struggle for another reason if I were to just stick to the "background/credit check" criteria. 

If you're using traditional financing on your primary residence, they're going to do another credit check on you just before closing.