There are a few things that will bother Your Editor And Publisher (me!) if you do them in a scene. That's not to say that if you do do them, the scene will be rejected, but it does increase the chances. I will try to work with you to fix any problems I feel exist.
For instructions on actually submitting a scene, see below.
Please remember that this is a Traveller web site, and therefore the stories must be Traveller stories. If it feels more like Star Trek, or Star Wars, or Dungeons and Dragons, or etc., it will require extensive reworking before it will be acceptable. That's not to say that Star Trek, Star Wars, D&D, etc., are bad, just that they're not what Freelance Traveller is about.
Any era of Traveller is OK. Setting the story outside of Vilani/Solomani (Imperial) space is OK (so write that Zhodani story if you want!). Alternate timelines are OK. Even alternate spaces (i.e., not the canonical stellar or political map) are OK. Even better is to write so that the reader can plug it into any era or location desired, mentally. There's a lot of leeway. But it's still gotta feel like Traveller.
Leave your scene open. Don't write it so that there's only one reasonable choice of action to forward the plot - the more possible choices that the character has, the more options for participation other people have.
Don't introduce technology, minor races, devices, etc., which would 'unbalance' a campaign if they were to appear in one.
Don't introduce new major races at all.
Don't introduce technology, minor races or characters therefrom, devices, etc., unless they are legitimately important to story progress. Even then, think several times before doing it. Hint for races: If the part could be played by an ordinary human being, it should be.
Don't introduce technology, devices, etc., that come from other SF backgrounds. This is still Traveller, not Star Wars, Star Trek, Battlestar Galactica, Lost in Space, Babylon Five, etc. It is OK to use terminology from other backgrounds that fit the Traveller 'feel' - for example, referring to the grav mechanisms in an Air Raft or GCarrier as 'Abbott Lift-and-Drive'.
At the end of every scene, there is a "Continuation Code", followed by a link.
If your email program allows the Subject header to be set in a mailto: link, all you will have to do is click on the Continuation Code link. In the body of the message, place a one-line description of the decision made, followed by a blank line, followed by the text of your scene. Make sure your real name appears in either the "From: " line of the message, or at the end of the body.
If your email program does not allow this, send email to firstname.lastname@example.org with a subject line of SCENE: followed by the continuation code at the bottom of the scene that yours wants to follow. For the body of the message, follow the instructions above.
If you're not continuing a story - in other words, if you have a scene for starting a new story - use a subject line of SCENE: NEW STORY, and omit the decision description, but otherwise follow the procedure above.
A sample submission might look like this:
From: John Smith <email@example.com>
Subject: SCENE: ABAABC (if this were the first scene of a new story, this line would be SCENE: NEW STORY)
Eneri decides that revenge is more important, and leaves the ship to go after his wife's killer.
Eneri had never been so angry in his life. For his wife to have been killed in cold blood like that - it was unthinkable that he should allow the killer to get away. ... etc. ...