That would be quite a feat to master that kind of text. I just stick with the simple ones because it's easier to use and faster to make. Typography is one of my weakest points so I try to keep it simple so I'll not mess up so much.
Hmmm there are two ways to stop attention from going to certain spots; blur or darken.
Blur is more popular because it's easier to use and more effective. Some people just don't like how blur looks so they keep it to minimal or none at all. Alternatively, you can just darken stuff. For background in general, just create a new layer on top of the bg and fill it with black color. Keep it in Normal and adjust the opacity. Around 10% ~ 20% should work. You could also erase some parts you want to keep bright for reasons. For the whole sig itself, use a soft black brush and brush it over the parts you don't want attention in a new layer. I usually use a really big brush on this one and brush it outside the workspace. You could also just use a smaller brush and precisely cover the parts you don't need. You'll need to adjust the opacity on this one. Use Darken/Overlay/Normal. Darken and Normal works the same with this one but Overlay is a bit trickier. You'll see what I mean when you use it yourself.
As for choosing what to blur and what not to blur, it comes in time, yes. Hmm as for me I don't directly blur stuff. I do it in the end and just use an inversed layer mask for the sharpening. If I can say any guideline, I only have the ones that cover the render blurred. Like those vector circles or something. And yes, most of the time I blur my backgrounds to oblivion.
Hmm for choosing backgrounds I usually stick with the ones that have the similar theme and/or color with the render. Although there are exceptions when I really want a background and adjust the coloring of it myself. You could manipulate the color of the render/background by using Selective Color. It helps a lot when you really need to fit two things together. Like I said above, I blur my backgrounds to oblivion because I'm too lazy to choose one myself. But the above guidelines should help.
The background you'll need with this render is kinda tricky. The perspective of this one is from above if I'm not mistaken so a background with the same perspective is a must. That or use abstract bg like you used with this one but add some c4ds to give a sense of depth. C4ds are really convenient to use since blurring them appropriately gives a really good sense of depth.
I'm glad if you're picking up some stuff in my blabbering. But practice is the key here so practice when you have some free time. Simply reading about this will help but knowledge + application is the one that'll be your best teacher.