This is a very niche request. I am not experienced in gundam art but You don't have to be experienced in gundam art to understand the principal theories being applied to the drawings or designs.
Understanding basic perspective and hard surface rendering should do it as far as drawing technique. If you need a little help finding the right video's to watch then maybe this 4 part series would help.
And if you want to understand the basic concepts that designers are taught in school and take the time to learn them you are going to learn more than you will ever need for how to design and draw gundam. https://www.cubebrush.co/foundationartgroup
If you dont want to go that in depth I recommend Anthony Jones's store to to get you started on some of these subjects to start to learn the shape language theories and the techniques to apply them using drawing or photoshop. These videos are not as in depth and much more approachable. https://www.cubebrush.co/robotpencildesign
When considering your own designs you must consider what problem your design solves. What is their intent? Flight speed? Then it's aerodynamics, rockets and light weight. Is it a big gun carrier like artillery? Then its large and able to lift heavy objects with specialized targeting.
Does it wield a sword and has to be able to perform close combat martial arts techniques similar to a human? Well then it needs to be balanced like a human male or female and choose a martial art or nationality. Designing is just problem solving. But come up with a problem or limitation like, a gundam that can only use a knife weapon. Now make 5 gundams that would wield knives. Its through limitations that creativity is born.