[quote=@Gendarme]
How do I do a proper collaboration post?
[/quote]

What I've usually done is set up a PM with the other party and we write it out with our own individual posts, and then mutually edit and work it out when it's finished so both are satisfied with the general flow. In this case we might recognize one of the two characters has taken a leading perspective on the matter and it'll be edited to that and posted by the player of that character.

[quote]
How do I portray ships, buildings, and inanimate objects in general through writing without sounding boring?[/quote]

Metaphors and similes are going to be your best option and is the most commonly used. Instead of saying, "It was 35 units long, 10 wide, and 80 high" find a comparison in life. "The masts were as tall as trees with a color like that of ragged decay and mildew. Its length was like that of a long street, straight and narrow. But it's entire size inspired fear and awe upon [the character]."

Using more abstract and less direct language to compare X to a more readily known Y can also help in reader connectivity because it allows them their own creative lee-way. Instead of describing something as "red" you might say it was the color of a strawberry sundae or cherry pie.

[quote]
What is the right amount of detail in most posts? Are there any exceptions?
[/quote]

This is unquantifiable and comes with experience. You will just need to write and gauge how readers react. RP or otherwise.

If the people you're writing with write long posts and you read them, then it's safe to assume if you write a long post they will read them. But if they're writing short-ass posts and you're writing long posts then it's safe to assume no one is reading yours.

[quote]
I intend to head to an Advanced role-play at some point, but I would like to increase my skill beforehand. Do you have any general writing tips?
[/quote]

Write, read.

[quote]
What early signs are there that a role-play will have longevity and not die out quickly? How can I help keep a role-play alive and fun as a poster?
[/quote]

When you throw the sacrificial bones upon the fire made of dead Africans and gas-choked Seattle hipsters and the flames turn blue. When the Chinese sing Kalinka. When skies over-head are clear and Tengri's summons are strong.

Then you may ride out from the German castle of Procstratinationburg and ride into the literary world of Russiya.