I have literally failed my way over and over again making every mistake possible in my real estate investments. 

I'm a newbie also and making alot of mistakes along the way but loving every minute of it.

You will learn the most by actually doing it....and it's a huge mistake for an investor to not understand the nuts and bolts of how to turn a house.  

•What has been your biggest mistake as an investor?

He's basically asking me to give him money for a mistake he made which resulted in me paying less at closing.

Since I started in 1978, I've had lots of practice and time to experiment as well as make mistakes.

@Francis A.I self manage, and boy, do I make some doozy mistakes.  

I made the mistake of overusing it for years and hurt my body, be careful if you can. 

My problem is spending too much on books which Im glad I did but I learn better by watching something and then the books will make more sense- I did it running a sound board at my church as I watched you tube videos and applied what I learned-then had someone come out and show me more and eventually I was fine- I am learning and understanding but until I know exactly what to do and I do not want to mess up- well not too bad we all make mistakes but this is a field where mistakes can be alot more costly. 

Learn the business, make your mistakes, learn from them, maybe even hire a Property Management company the first 2 years.