I am a first time writer, and have a story idea that I would possibly considering writing. It involves my younger brother, , and would possibly consider multiple chapters, any suggestions or help ful hints.
Well - you haven't given us anything to comment on. Is this incest? Usually a good story. Is that gay incest? Even better (for me). Is this group nonconsent/reluctance incest? No interest (from me). I think you need to give us a little more before you start getting serious comments / suggestions / opinions.
You might want to work on your Thread Naming Technique. This is a forum called Story Ideas. To name your thread Story Idea is not the greatest notion in the world...... it conveys ZERO information to people who might be thinking about which threads they want to read.
Even as a first time writer you sound so tentative ("would possibly considering ... would possibly consider ... any suggestions") that it appears you lack confidence. This is a free site with no barrier to posting your work beyond a few restrictions on subject matter, and basic readability. You don't need hints or suggestions to get started:
Go for it.
You must already have a basic idea of what you want? Any story about a twin brother and sister will find an audience. (Over-18 is all.) Write down what you have, edit what you can, and post your work for the world to see.
Do it now.
You might not get the response you hoped for, but it also won't be as bad as you fear. The next story will be better.
As I mentioned in an earlier posted thread, I would like to see someone write a story about a brother/sister non-consent story, where the brother makes the sister step way out of her comfort zone and do some exhibition. Twins would make it even better, the older brother could have them both exhibiting and even force them to have sex for spectators. Just a few thoughts! If you decide to write it, let me know.
So, who are you? A boy? A girl? Older? Younger? Is every possible character eighteen and older? Will you three fuck? If so, why? If not, what direction are you going with this?
The bulk majority will not be able to "help" you without more info first.