What is the difference between やる and する ?Feel free to just provide example sentences.

やる vs. する

Today I will explain the difference between the two verbs yaru (やる) and suru (する), because they both mean “to do”, but are used in certain ways. This tends to confuse people a lot. So without further ado:

する is the common “to do”, and comes after many nouns to turn the noun into a verb (ex. 想像 vs. 想像する, “imagine” vs. “to imagine”). する can be a verb on its own, but in many instances just comes after a noun to turn it into a verb.

やる also means “to do”, and can be used in place of する, but not usually. 

The difference between the two? やる can only be used for physical (active) verbs whilst する can be used for physical and abstract verbs (abstract meaning things that are not physical, like imagining). For example:

ゲームをする - do game: game + do
ゲームをやる - do game: game + do

やる works in this instance because doing (playing) a game is a physical verb that we do with our hands and whatnot.

勉強する - to study: the noun “study” with “to do” after it, turning it into an action verb.
勉強やる - do study: studying is an action suru verb, so using やる would still be correct (just a little bit unnatural).

夢想する - to dream
夢想やる - WRONG!!!!!!!!! dreaming is not a physical verb, therefore やる cannot be used. 

In addition, やる has become a bit of a vulgar word in today’s world as a lot of the time it means “to do”, as in “have sex” (just like the English “do it”). So, when in doubt, just use する、even if it may sound unnatural.
Example: If anyone has ever seen Kill Bill, the subtitles for Gogo Yubari says in one part, “Do you want to fuck me?” to a creepy pervert at a bar. Technically, she says, “Want to do?” – “ やりたい？”, to which the subtitle for the creepy pervert says, “Yes.”, and technically he says “Want to do.” – “ やりたい。” And then Gogo stabs him and laughs maniacally. nbd, just your everyday thing. 

I think the best indicator of whether やる is correct or not is if you can use を at the end of the sentence. If so, you can in many cases use やる and する interchangeably. As a matter of fact, you can use both in the same sentence:
俺は彼を射殺してやる。Ore wa kare o shasatsu shite yaru.
I’m going to shoot him. (lit. I to do shooting him.)
See how “to shoot” is a suru verb?

The most important thing to remember is that やる NEVER comes after an abstract noun-turned-to-verb. It is ONLY used for physical actions of doing (shooting, playing a game, killing, etc.).

There is a lot more to using やる than what is covered in this post, but this is all I’ll cover for now. I hope this has been helpful, and special dedication to pint-sized-slenderchick for bringing up this question. :-)