I've since sold them.Now I only flip to sell, low volume, high margin.

Marginal business practices, bending rules, short cuts... all caught up with him and those (generally) who were not a "quality mentor" or a "quality trainer".

Make sure you’re prepared for these challenges, especially if your cash flow margins are tight.Spousal Agreement:It’s important to have your spouse on board with your investment strategy.

No reason to hurt your margins if you can spare the time. 

My latest theory is that anyone in that area who's responsible and earning a living can afford to buy their own place there, so what's left is a renter pool of marginal folks.

While you assume $3000 in rent with a mortgage of $2500 leaves you $500 in cash flow the reality is that after factoring in the above amounts and any other expenses you will quickly realize that your margin wasn’t good enough and you’re really at $50/month cash flow or even negative.

Strive to build equity rather than focusing on properties with a narrow cash flow margin.

A lot of the land investor community focuses on volume and land deals below the 5k buy/sell price, so title companies eat up that margin.  

People think that if they can go it alone they can improve their margins and costs.Unfortunately, this backfires more often than not and I have stories for days (as I'm sure many other providers do) about investors that get absolutely destroyed going it solo.

In my humble opinion, rent estimates are typically off by a wide margin.