You MUST learn the scales first, at the very least. The chords follow and then the embellishments.

There is no shortcuts if you want o be able to figure it out for yourself.

The circle of 5th and 4th are great tools for finding key signatures, but I disagree that they help find the chords in any given key. That's simply not true, according to what I've learned. There are infinate combinations of chords within any given key, and following the 5ths will not get you there.