When trying to break into the world of real estate, it gets nerve wracking. The hardest part is securing capital that can help support your system. To do this you may have to take a gamble on yourself and leverage all that you own for your future self. If you can read that and you are fully comfortable with it, then you may have what it takes. First you need a dream, you can make it anything you want, a 3 month vacation in the Caribbean, a brand new Porsche, 10k a month in passive income, or even just being able to go out to eat once and a while. Mine is 10k a month of residual income. 
The road to success is bumpy and has even put people I know into the hospital because of stress. This is something that can free you, and your family from financial constraints, or it will tear you down to the ground and make you start at square one again. If you are truly okay with that reality, then I feel that you may be ready. I personally believe that you need to have a plan b, c, and d for every investment. The market moves in cycles and if the cycles change while you are heavily leveraged, then you will not make money. You need to have a back up plan for that. Mine is a little saved up cash to help if the market unexpectedly flips. 
I bet you are reading and saying that all seems like fluff, get to the point of how to break into the market, even if you have no money. Well here are two ways how to break in. First become a property finder. There are properties that you can buy right now in Denver for 70 cents to the dollar. This means a 300k property will show up for 210k. And your Real Estate agent will tell you it is a great deal getting a property 15% below market. To become a finder you need to pick a neighborhood, and comb through it at least weekly. start meeting the people there and learning their stories. Pull public records on the properties and look at their tax information. If they have a different tax address then the house address, there is a good chance it is an investor. 

Market valuation is easy, it is what is moving in the market. If you find a subject property that you are interested in, yet you are curious to see if it is undervalued or overvalued, follow theses steps. 
1+ Go to Realtor.com or Zillow or any site that can show you recent sales. 
2+ create a radius around your subject property and look at all sales that have sold in the past 6 months
3+ Create a table in Excel showing the sold price and the square footage of the twenty properties.

4+ Create a scatter plot graph in excel where Sold Price is on the Y-axis, and Square footage is on the X-axis. Do this for at least 20 sold properties. 
5+ Create a trend line on the graph. The trend line is the average price per square foot that is moving in the market.
6+ Match your prospective properties square footage to the graph and see where its price falls compared to the rest of the market.
7+ if your property is below the line, it is under valued and you will be able to offer more for the property, and if it is above the line it is over valued and you can offer less.