How to Win at Monopoly® - a Surefire Strategy

Always thought I was good at the game, until I read this:

"Always buy Railroads; never buy Utilities *
At the beginning of the game, focus on acquiring a complete C-G (Color Group) in Sides 1+2, even if it means trading away properties on Sides 2+3. After acquiring one of these C-Gs, build 3 houses as quickly as possible: no more houses, no less!

Once your first C-G starts to generate some cash, focus on completing a C-G and building 3 houses in Sides 3+4.

Note: 3 houses is the "sweet spot" in the game as shown in Table 1 below. That's where you're making the best use of your money.
Single properties are the least good investment if you don't build on them.
..."

From: amnesta.net