When funding is rare and flips are plentiful, there will be enough opportunities for everyone but return will be depressed and better operators will make better returns. 

Operations- tenants refusals, either cull them before they get to you by requiring autopay as an example, document on their application why you refused them, make sure your facilities are maintained properly and no safety hazards exist, etcLLC.

Use an operating account for income and expenses, a reserve account for maintenance and taxes, and a high-yield savings account (HYSA) like Capital One's 4% APY for idle funds awaiting reinvestment.

One thing I would mention though - doing STR just to save taxes often leaves you operationally unstable or too detached from the management to be successful.

Quote from @Carlos Lopes: Gross income doesn't matter.This is the number most people post, and it's 92.7% useless.What you need is NET income, meaning the money left over after all expenses, and that should include a dollar amount for your personal time spent operating the business. 

Also, depending on your long term goals, transitioning part of your portfolio into more passive investments might help reduce operational stress while keeping your equity working for you.

If you can hang on into next spring/summer I bet you'll get better rents or be able to sell.How about asking your lender to push a monthly payment to the end of your term for the purpose of fixing the asset?

Simply document everything you do and create your own Standard Operating Procedures (SOPs).

What tools have worked best for you to streamline operations? 

15 acres for a lot sounds huge to me and I'll bet you could be missing out on some extra $ by not getting more lots.