Everything runs out of steam... I wrote one amazing screenplay , I worked on it and casted in in 2014 and 2015. I wrote 6 drafts but left film in July of 2015 with it never been filmed for personal reasons (don't ask). I'm burned out on makeing this story and wonder should i make another one knowing in my mind this is my peak the best thing i ever write. Should i settle for below average ideas? Ideas keep going through but i scuttle them ..none of them move me the same way.
The thing is that if you feel that your story will go downhill if you force yourself to write, then don't. Move on to the next story. The last thing you want is to have a piece you love tainted by work you feel is less than the original. Never settle for below average ideas.
I already wrote Euphoria and the sequels are just outlines however I doubt myself now looking back if it's genius or average or good ..i want to believe it's great.
So then just write with the thought that this is a test run. Take a step back after giving yourself enough of the story to see if this is heading in a direction your intrigued with. If you are satisfied/happy with the results then keep moving forward. If not, then back to the brainstorming and that is ok to do. I got that.
I felt the same as you with my first story but realized I got too many stories in me to just sift through them or wait for another big wow moment to happen. Not everything that I create will be impressive, or amazing. Some of it will just be practice or things I do for fun. Some of it will be downright lame. The idea that one's creation must be amazing is counter-productive. If you're only working on 'great pieces' how can you get in the proper practice to make them great? How do you decide what will be amazing and what's just average? I've worked on stories that I thought we're just average and found that they've held some of my deepest insight. And some that I thought had more relevance held some of my corniest, forced, themes ever. I never know what will be great. I'm always searching for the next step in my writing journey. And I try not to look at it as a stairway that goes up or down. To me it's always steps forward.
You might start by working up loglines for the new stories. If they pass muster there, go on to outlines in either point form or prose. It won't (or shouldn't) take up too much time and the process should give you a much better idea of whether or not they're worth several months (or more) of your time.
It's strange but I don't feel the same way. I feel maybe I'm a novice learning and it can only get better. I know my story is going to be told over several books so I have ideas that keep coming to me and I like to think you are continuosly learning no matter how advanced a story writer you are! I see that some people are saying to move on but why? If you are in love with your story and you have put a lot of effort into it but it didn't go as far as you would have like then why give up? Maybe you can change the story a bit, update it? Or if your happy as it is then try re-releasing it again, what's the harm? Or self publish it? I don't know, I just know I wouldn't give up on my story, I would want to take it further no matter what, I've put too much effort into it to just leave it.
Unless you've contracted a degenerative brain disease @DrewRights I can confidently say that if you stick at things; you'll get a whole lot better. I think peaking at 30 maybe good for sport and mathematicians but in this game one can be afforded decades for improvement.
Practice and perseverance are key to becoming great at something, not in abandoning the things you love when they don't turn out the way you want them to. So don't give up on your writings just because you have doubts. We all have our moments when we hit a mental block, or have to revamp an entire story to make it better than what it was. Look on the bright side, at least you are a writer and don't have to cover up the mistakes with more layers. You can simply delete the offending bits, and write in the new pieces that will make it great.