Making good GFX is actually more complicated than simple post-processing effects.
Here are some major considerations that should be taken into accout:
Colour:
Colours are one the most important parts of any GFX or artwork. If you get the colours wrong your image can look too complicated, too saturated or under-saturated – lots of issues.
What you really want to do is to choose 2 or 3 colours that work really well together and help with what feelings to you want to show to a viewer.
For example if I was making a indoor scene that I want to feel warm and cozy, I’d keep colours to shades of orange/yellow and an accent colour of anything else that doesn’t clash.
Here is an artwork I make last year, as you can see almost all the color is orange/red with the exception of the hangar shields on the ship. What’s important about that is that you’re not being distracted by 50 different colours, instead your eyes are drawn to detail and the contrasting elements.
Contrast:
Having proper separation of what is important in your scene is important as it can be used to draw the viewers eyes to places you want them to look at.
For example, in the artwork above the planet is very bright towards the left but towards the right it is much darker which allows us to put a big bright ship in that spot.
If we put that spaceship in a bright area it would be hard to us to separate it from background and so it wouldn’t be very nice to look at.
Furthermore contrast can be used in one other way and that is colour contrast.
Usually when we thing of contrast we think of light and dark areas but contrast can be much more than that.
Take for example another older artwork of mine (yes I know, the planet is terrible and the lens dirt is wayyyyy overdone)
As you can see, the brightness of the planet in the background is not too different to the brightness of the rubber duck but we can easily separate the duck from the background in our eyes because the colours contrast each other.
Importantly they don’t clash either, the blue + orange/yellow is quite a nice combination and so this entire scene can be summed up by just those 2 colours.
Finding good combinations shouldn’t be too hard, it just depends on the mood of your scene.
As we’ve seen, red/orange + blue work quite nicely together, personally those colours are my favourite but it’s different for other people.
Red + Cyan, Dark Blue + Yellow, Purple + Green are all what we call “complementary colours” so if you’d like to learn more about that, google that phrase and you’ll find some good tools and articles.
Detail:
Having enough detail is very important, you can have too little and you can even have too much. You can get away with low detail more often if you are working with style and not realism but if you’re doing that you must keep your colours, lighting, contrast, etc also simple so as not to make the scene feel off-balance.
Now this is possibly one of the oldest renders I have from about 4/5 years ago, and it’s awful. We’re gonna use it show a very bad balance of detail:
Bad colours and contrast aside, the details of this scene are not pleasing to the eye. This is for several reasons.
Firstly, look at the background… the stars seems are bright as the ship itself!
The separation of the ship from background isn’t right because although the background is definitely darker on average, there is simply too much stuff going on that your eyes don’t really have a place to rest.
The other part of this is that for all the detail in the background, the ship doesn’t have nearly as much detail to match it. The hull is almost completely smooth save for some turrets and noise patterns. It’s just boring. You look at if for 10 seconds and you can no longer see anything new.
So this scene suffers from both too much detail and too little, I put the details in the wrong place, there should be little in the background and more on the ship.
(Also those lasers are disgusting but we won’t get into that.
Conclusion:
At the end of the day it’s gonna take you some time to learn about this. The best way you can learn is by practicing. Make new scenes, maybe after a year or 6 months of progress you could open up an old file and try to remaster it. You can compare what you knew back then to what you know now and see how far you’ve come.
Importantly, have fun while you’re doing it! Do projects and scenes that you want to do and look back to see how far you’ve come.
I’ll leave you with one more comparison, here is that ship scene I made all those years ago, and one that I made a few weeks ago in the same amount of hours.
Let me know if you have questions!
Good luck my friend. 
wow esto es asombroso
:this is amazing
