What factors/metrics do you look at to determine if a market is crashing or shifting?

Over the years i have been extremely passive with the business and never took the time to really learn how to property invest in real estate, i just assumed i was doing things correctly, i didn't know how to do the numbers, just went with the flow.Since im down to 5 rentals and i made a very small amount of money selling off the negative cash flow rentals that just never recovered from the market crash in those 2 areas, since i bought to high in the peak of the market prior to the crash. i decided to apply for a mortgage to purchase another rental in my local area using some of the new knowledge i have learned recently, but after applying for multiple mortgages most of the places i applied basically said no, that cash flow to money lent to me is in a risky zone, basically i own properties that were not bought with rental numbers in mind, so turning them into rentals they barely cashflow except for my very last property i purchased that i did basically a flip on, that left lots of room between the mortgage payment and rental rates in the area.

After the late crash I put down earnest money in the amount of the full offer.

It was not purchased as a rental at the time, but due to the crashing market, it was/is underwater and I had to convert it to a rental because I couldn't sell it.  

So, given that there was a crash 10 years ago (and some people forecast another big one soon) and there are plenty of investors that do ultimately fail in healthy economic times, what does that look like, and how do you recover?

Essentially what @Omar Khan is trying to explain is that the high prices are due to very high demand and the only way that the market will collapse is if the demand disappears, which I cannot see happening with our high immigration rate and while ever everyone still only wants to live in the capital citiesDon't be fooled by the media speculation and articles posted on news sites etc about the "bubble burst" and "housing crash". 

But after being burned in 2008 after I bought my first rental property I was done with real estate investing after that crash.  

I have money though and I have rentals so I understand bookkeeping and managing tenants etc. but when i bought it was after crash so, it was easy.

I personally won't be buying anything until the crash happens and the bottom is found, but tons of other people think there is still a lot of room left for growth.

As you know, we'll probably both make more money buying multi units in Central Maine vs. vacation rentals any day, so even buying a few VRBO's here and there for fun and to  have a place to crash doesn't really make alot of financial sense.