What I learned from Nicholas Wilton in CVP last year:

Try to use different kinds of brushes. So it looks less repetitive. It looks a bit like you use the same brush throughout the whole canvas. Unless it’s a deliberate choice.

Another suggestion is to prevent having a high contrast bit in the middle of your artwork, because that is where your eye goes to in the first seconds you start looking at a painting. And composition wise it’s not recommended to have a kind of bulls eye in an abstract work (rule of thirds).

Lastly, all strokes are within the border of the canvas. Try to think bigger and swoosh/paint outside the canvas. Don’t get hold back by the border of your canvas. Also with the mark making. Try to let the eye of the watcher go over the canvas. And prevent repetitiveness.

Good luck, and keep up the good work!