I began, like you, as a buy and hold investor but have ventured into a couple other areas as well.Be sure to check out the podcasts for concentrated and entertaining REI education. 

Haven't listened to it in a while, however do remember it was very entertaining.  

Any city or state that highly depends on travel, entertainment & hospitality will probably be hit pretty hard.

It is an entertaining, enlightening, and inspirational true story of my first few deals.

@Shiloh Lundahl and @gary Leonard thanks for my entertainment.

He provides a genuine perspective and the books is easy-to-read, entertaining, and shows the daily ups and downs of a house flipper. 

At the end of the day, you just have to keep an eye out on all sources and learn to sort out the old listings and trash...though some of those come back on the market too and you can ping that broker asking if the seller has any others or if that one is having issues closing.  2 of the last 4 deals we did were MLS (6 unit and 32 unit) and 2 were off market where a broker we knew said the owner would entertain an offer (20 unit and 12 unit). 

I entertained a few ideas of partnering with some other individuals like myself to start together.

Some owners might entertain the idea, but it’s also important to note that not all owners are in the market to sell, making rejections relatively likely.5.

See if they're interested in selling or would entertain an offer if one came in (almost all will at least look at one).