This is a common question painters are asked, particularly of abstract work. The more important question is what are you thinking as you look at that? What are you feeling? For myself, I say, it often has nothing to do with what I was thinking about and everything to do with what lies beneath the thinking part. The feeling, spiritual process that goes on unconsciously is what I believe comes through to the canvas. I think of an abstract painting like meditation. More experience, less thinking.
Certainly their is a delicate dance between pure expression and critical thinking that goes into a painting. There is evaluating composition, how colors play together, the energy of the lines and forms, etc. and solving problems. Initially, I give those things minimal attention. As a beginner, you may pays attention to the latter focusing on technical aspects which can produces a painting without expression and feeling. Purely decorative. In my experience, strategy plays a role only when it is necessary leaving as much space as possible for spontaneous expression.
Currently, I swing like a pendulum from full expression to careful critique. I paint with abandon and then pull back and evaluate what needs to be quieted, balanced, or eliminated. A gesture, a step back, and again as I refine the work.
There’s also a considerable chance I am thinking about who needs to be fed, taken outside, or driven somewhere. People have romantic notions about artists, most of us show up and do the work just like any other worker. Skill, time, patience, dedication. Repeat.