You can read a book and multiple books, but unless you are out there doing it (I.e. getting bids and getting contractors to truly get you an exact estimate) you will be far off from the numbers you want and may even lose money on the flip/rehab.The best advice I would suggest in my experience is that you should get into the line of work by either partnering with someone or working with someone on some projects prior to going into a flip on your own.

So, if you are shopping around, trust your numbers and don’t be aggressive on price, you may be only bidding against yourself.

UpdatesI have two BIG updates, I actually just closed on a home not for airbnb but for myself in an area I have been trying to buy for a year but investors have been bidding on houses like crazy in the area.

Having a solid contractor who can give you bids helps for sureLessons Learned:I have had a couple of clients out of state not fly out and see their property in person & then be disappointed about some things after closingGeneral Tips:I'm sure you are well versed in the Dallas Fort Worth market but this is a nice little tool to have https://www.areavibes.com/ this website gives you a nice overview of streets and zip codes and a total livability score. 

There are plenty of sites you can bid the vertical work through.

If they move soon, one month vacancy would eat away any savings of a hard "no" and it's wintertime (here) where vacancy is harder to fill...I'd at least discuss with the tenant and have someone do a bid to find out what it even costs for this home.

Design choices should come from you and you should discuss them with the GC as part of the bidding process.

When I shop for new vendors, I pick who I like the most and has the best reputation, not who bids the cheapest.

I'll make an offer that works for me and then someone else will bid slightly more or way more. 

Lastly, I make sure that we are double checking and doing proper due diligence - I walk the property and do an in-depth investor walkthrough for them, we do a home inspection, we have a licensed GC to walk and write up an itemized bid, etc.And to answer the last part of your question, one of the hottest markets is Columbus Ohio!