A nice quick guide. Definitely eliminates a lot of experimentation when in hurry to get going.

Here's a 10 second theory class: stick to the four principles of design - remember CRAP (not my theory though)

- C: Contrast -> use contrasting design to make things that are supposed to be dissimilar look dissimilar.

- R: Repetition -> repeat design patterns for similar items. Remember CSS?

- A: Alignment -> don't leave anything just hang in air on the canvas. Align things together.

- P: Proximity -> birds of the same feather flock together. Similar things are closer. Dissimilar ones are farther.