Wellcome to BP @Andrew Butler,
The BP Podcast is great place to start and learn about Real Estate, it has content to all levels and like yourself, I'm hooked.
Considering your questions above I would like to recommend you listen or read the book Tax-Free Wealth Written by Rich Dad advisor Tom Wheelwright I JUST finished it and its great. Highly recommended to any REI. And it will answer your first questions and will show you how the Rich don't pay tax, often At all! There are so many tax incentives in the US Tax system that i was blown away.
To pay yourself first means simply this: Before you pay your bills, before you buy groceries, before you do anything else, set aside a portion of your income to save, some say 10% of your net income.
If you put these saving towards ASSETS that produce income like Cash Flowing Real Estate you can use this cashflow to pay off you liabilities.
Im not sure exactly to which part of the "not paying tax" on the income you are referring to, but there are many ways that this could be done. (and the book cover them all).
One way that Rich Dad is referring to Tax free income is by refinancing assets and pulling out equity which is affectively tax free cash. this is not my favourite strategy as if one keep doing that regularly one just create more and more debt. this strategy is safer in high capital growth environment but very risky in no or slow growth market.
Another way is to off-set your income with chattel and building depreciation deductions from your rental property.
In regard to your situation, I would start with listening to the book and then consulting a good CPA.
Although BP is great and there are some very experience people here, I always think that seeking professional advise is money well spent.
All the best.