On a positive note, I hope. Look at it this way. Skill is something you learn not something you haven't got.
I remember an art tutor looking out of the window. He then dipped his brush in a few colours, mixed them together, painted the result onto a sheet of paper, and lo and behold, the colour of that day's sky. "How did he do that?" I wondered. After a few years, and lots of painting (I don't use the word "practice"!), I was able to do the same (I was in my 40s at the time).
When I started modelling, I saw some amazing scenics, weathering, and you name it, I had never done it. So I asked, read the mags and joined RMweb (2012), went to exhibition demos, bought a variety of modelling stuff (foliage, powders, etc) and had a go. Tried it out on the back of an envelope, cereal packet, whatever. If it worked, I did it on the layout. I think the key is breaking it down into component parts, then working out what you need to create them - man mowing lawn = green (summer) fibers for grass to be mown, brownish (autumn) ones for shorter grass that has been mown, and some static grass fibers "suspended" in the air over the blades of the 1950s lawn mower with Tacky Glue, and a pile of freshly mown green fibers in a corner of the garden.
I am no expert, I am learning all the time. I model to what looks reasonable to the eye. But beware - take a photo and it will probably NOT look alright! You only have to look at photos in the mags where, for instance, scenes and objects of a layout are printed larger than life. The camera, as they say, can be cruel. On the other hand, you can use the camera to help you find things that have been missed, need touching up, or doing again. It is also an excellent tool for showing you that your efforts have worked.
Hope this helps boost anyone's confidence to gain any requisite skill so that you CAN go the extra mile or half!
And in case you are wondering - my plan for this winter is to learn a totally new skill, the art of soldering small brass components... wish me luck!