Focus on one or two target markets, get familiar with the numbers, and use tools like BP calculators to analyze potential properties.Whether you start now or after graduation depends on your bandwidth, just have the right systems and support in place first.

If you can show that someone else has paid the loan on-time for 12 consecutive months you can exclude that debt from the debt to income calculation.

BTW behind Texas.When all forms of taxes are calculated (income, property, and sales tax), CA ranks below the middle of the nation in total tax rate.  

For market pricing, I collect LTR data from BP rent calculator and multiply by 1.5x.

It's worth looking at a blended rate calculator before you make a final decision of the type of loan as it will show the new "blended rate" of your HELOC and first mortgage if you go that route.

When you run numbers in a BP calculator you can see quickly that equity gains DWARF cash flow.

I’ve even had structural engineers say that a deck or other structure should have fallen down as well, according to their calculations.

A solid agent can help you calculate ARV, manage inspections and contractor connections— get quotes and coordinate handymen and vendors post close, provide shopping lists and software suggestions for management or STR furnishing, etc. 

All the BP calculators I've seen are based on LTRs. 

There are several websites available today that will help you to calculate potential rents.