Alan Flusser (yes, our guru again) has often stated that the place to begin your sartorial awareness is to learn to wear a simple two color palette well. Something like a dark suit, white shirt, dark tie and shoes. It is harder than it sounds, believe me. It is very easy to fall into a shapeless lump of grey or blue.
I think that your next step is to learn patterns and how they rely on scale to play well together. A case in point, blue blazer, white handkerchief, white and blue ‘pane shirt, and blue and white striped tie. The shirt and tie work (I hope) because of the differing scales of the pattern and the reversed palette. The shirt has a primarily white ground and the tie a blue one. I couldn’t resist adding in a little texture — the tie is raw silk.
Choosing lighter or darker suits depends on your coloring. Despite my soon-to-go beard and greying temples, I am clinging to a high contrast look which works well with the stark contrast of navy and white.