Hm, of course, rather subjective, but I give you my two pennies. At the risk of tooting my own horn, here are some of my similar abstract scribbles.
The image above seems to start with the centre circle, and two flame-like shapes coming from that. The artist has brought in a contrasting/contradictory part to one of them: the "jagged" line at the bottom (gives me associations to negative space and cogs). This gives it a little of a "surprise": the image consists not only of identical wavy-flamy shapes. You want some contrast in there. Note also that there are repetitions of some shapes.
- Start with one simple strong shape. Do not overthink, and add
contrasting shapes to "grow out of" or counterbalance.
- Repetition can be very effective.
- Contrast in shape is (often) useful/necessary.
- In the beginning, simple ink drawings might be the way to go (pencils
etc gives too many additional options to keep in mind). Black and
white can be extremely effective and delightfully dramatic.
- Maybe most important: learn when to stop. Often these things gets
overdone, and the strength of the abstract can often be in the
deceivingly simple.
- You can find abstract inspiration around you: maybe the shape of a
part of a chair can be a starting point.
...and yes: doodle. Doodle as much as you can. Everywhere, on everything.
Edit
Right, here is basically how I do it. I rarely have an image in my head beforehand, it pretty much grows organically. What often happens in the process though, is that I sometimes wish I hadn´t outlined too far ahead. As it grows I see new things, and would like to have one shape above another (but I often realise this too late). However, I do not bother doing the same thing over again, it just goes into the mental database for solving abstract doodles.
I do not like to pencil it out first; it interrupts the process (I do figurative and pencil drawings too, but that is a different thing for me.)
It is interesting questions you ask, because I have not really thought about this in this way, so I am learning something here too.
Mostly, I would say: do not stress it, do not think too critically about it. Just doodle away, sometimes you will surprise yourself, and you will create a little, perfect doodle :-) Do ten post-it-doodles a day.
Basically, I have two approaches:
First method:
I start with a small shape, such as a little circle, drop, triangle, spiral etc. Then I expand with lines and shapes from that. This "second" level is often quite random, but it comes from a feeling for what can balance or create an interesting contrast. When I get tired of making one type of shapes and direction of movement, I add other, contrasting ones.
Sometimes the "centre" can be other things, text:


Second method:
I start with a line. Usually a long, curvy; often spirally one. These drawings do not have a centre as described in the first method. They often end up with a like ribbon-like structure.


General design:
I am not a fan of symmetry as such, so I like the variation of "imbalance". I find the combination with contrasting shapes more interesting. However: a certain amount of repetition is a good idea. I think a good deal about texture, contrast, balance.
Learn when to stop:
I often leave tiny doodles, thinking I continue them later. When I go back to them, I often find they have a pleasing self-containment, and adding more is not really going to make it better.
Digitising:
Most of the doodles in the link I gave you, are photographs of my moleskine sketchbooks. I sometimes scan, and sometimes digitise with photoshop and then vectorise with Illustrator. Here are an example. It was originally a tiny drawing on bad quality paper:
Photo of sketch:

Photoshop digitised version:

Illustrator vector and colour play:
