K so this is going to be a WIP for like a week or so, but I'm putting this hear because people are clueless.
A Guide to Concept Creation
-Firstly, get competitive experience. I don't just mean in OU, I mean in general, because it is really, really obvious if you don't know what you are talking about. If you're concept mentions pokemon like "Anger Point Tauros", or "Torterra", or "Castform", I will infract you, period. Currently, CAP makes pokemon for the OU metagame, and even if that changes, CAP's metagame will likely have a large percentage of OU pokemon in it anyway, so please get an idea as to how the game works and is played. There are usage statistics onsite, there are SQSA threads in every tier forum, there is the Battling 101 forum, there really isn't an excuse for not having a basic understanding of the metagame. Learn it, or hold off on posting concepts until you do.
-Next, check to see if your concept isn't already accomplished by an already existing OU pokemon. Again, it legitimately takes like 10 seconds to make a post in a SQSA thread saying something along the lines of "Hey guys I was wondering what strategies or pokemon people use to counter Volt Turn". If you get an answer like "Garchomp", then don't make an anti volt turn concept, because we don't learn anything from it, the concept already exists in a pokemon.
-Next, check to see if your concept isn't already done by a CAP pokemon, OR a previously accepted CAP concept. Seriously, read approved concepts, because not only does that give you an example as to what a good concept looks like, you can be 100% sure if your concept is/isn't already similar to an existing concept. Which means you avoid wasting both mine and your own time. Its win/win!
-Check to see if you're concept is viable. Just because you might see Tyranitar in OU does NOT mean that something like a weather pokemon CAP is a great idea. Obviously, their are subjective examples that might be an exception to this rule, but please think about if your concept would actually work in OU. An easy trick is to look at a concept, imagine what you think it might turn out like, and then think "would I absolutely use this to achieve #1 on an OU ladder. Not to use it because its "cool", or uses a gimmick that you always wanted to see used once. I mean, can you see yourself using this pokemon to actual success, rather than novelty value.
-Don't railroad. Seriously, if I see a concept that ends in "This pokemon should use Prankster or Magic Guard" I will call you out, because that concept is illegal. I want concepts that are versatile, that gives you options on as many stages of the process as you can. Making a concept around a particular move is fine, making a concept thats essential towards needing a specific typing or ability probably isn't, because it creates 0 discussion and TL/ TLT hate that with a passion. Pick something with multiple different avenues to explore, without making it too general.
More later, I could prolly write a novel on this.