Hi guys! I'm making it a priority for me to start making some how-to threads for this wonderful community.
So, a problem I see a lot on our server is sale message issues.
Unlike on .ORG, on .NET, you must set up your own auction if you wish to sell items. You have to make a message in chat, and get replies. Sometimes this can be a bit tough. So I am here to help, with personal experience and observation.
First, let me begin with an example of a BAD sale message.

@#@#@#@#@#SELLING- potato!!! 1 dia! #@#@#@#@#@#@#@

That kind of message is very spammy, especially when repeated over and and over, like a lot of sale messages are. So here are the components of a good sale message, at least in my mind

1) Use correct spelling and grammar.

Ex: Selling diamond! Please /msg me offers

2) You can add accents, just don't overload them! (Especially useful for non-donors, as they don't have color to help them stand out)

Ex: **Selling 1 Diamond! /msg me offers!**

3) In the case of auctions, make sure every component in organized. Only say your message every chat bar, or you could be kicked o(r temp-banned for spamming. DO NOT fake bids to make people bid higher. That is why it is nice to include the username of the bidder in the message to prove that someone has actually bid that.

Ex: Selling: 1 Diamond SB:10 grass HB:12 grass by Gemma
Tip: SB means Starting Bid, and HB means Highest Bid. Other selling talk? SC means Single chest and DC means Double chest

4) Do not spam your message. If you say your message multiple times and get no offers, your price may be too high, adjust it, or throw something else in, and try again.

5) Try to find the approximate price of an item before you buy or sell. Be realistic here. Nobody is going to pay a diamond for your two grass. Find what you can actually buy though, like some iron.

6) Be exact in what you are selling. Use numbers. For example, instead of "Selling potatoes, 5 grass", which is vague as to the number of potatoes being sold, say "Selling potatoes, 5 grass for 5!" This makes sure both you and the buyer know what they are going to receive.

7) (This one is for donors only ) Use color wisely. Don't use too many or it could be color abuse. I in general would stick to 2, maybe 3, colors a message. Try to use colors that work together, and are easily visible in chat for the best results. An extra thing I like to do: match the colors to what you are selling.

Ex: Selling: Diamond! SB:10 grass HB:12 grass by Gemma!

Note: I know those colors don't show up too great on chat, but I know that they do well in the chat on the server

I hope I helped someone out with this, and I hope you all can make some good sale messages. Best of luck selling!