Consider the medium. It's for all intents and purposes the capsuleer version of IRC, allowing for a few varieties of presentation like pure text, audio, audio/visual virtualized (my preferred option, it's so weird to me so many capsuleers almost never are in the pod), audio/video webcam style etc. Each user can also decide how to parse the feed, so they can have their systems convert it all "down" to whatever choice they feel appropriate.
Out of Character, consider the actual mechanics of it. It IS a damn IRC channel with severe limitations.
To me, this together means that 'descriptive' stuff should be kept to a minimum, to avoid pointless flooding and instead be used only when it adds significantly to the context and subject involved. To keep it somewhat rich, establish certain things elsewhere. Character descriptions and visualizations elsewhere will give other users a lot of baseline to work from, allowing you to just do minor things that doesn't flood/interrupt. Smirks, crooked smiles, twinkle in the eyes etc etc are all more than sufficient 'flavor' for a lot of things, if the rest of the characters visualization is already established. It doesn't add to the RP to describe the intricacies of the uniform of the day, or that the character is sitting at a desk or whatever, unless it's very relevant to the subject at hand, and has some kind of interesting hook to it. Another option is to keep it simple just to add a tiny bit of flavor and variety to break up the pure text. A small mention of a steaming mug of whatever (I overuse this, admittedly) might add a little bit of mental imagery for others to latch on to, and can be an emotive tool through the conversation. Hiding a smirk behind a sip, or raising an eyebrow above the rim of the mug during a sip, or just folding ones hands around a mug while thinking, etc etc can be very short emotes that doesn't add flood, but might add a little touch of "this is a character, not lines of text on a screen". Just intersperse it into the flow sparingly. If it's in every damn line, it just floods pointlessly.
The ultimate sin is breaking out the fucking thesaurus, or getting overly into the minutiae of mundane bullshit. I genuinely loathe the kind of emoting that takes eighteen lines of 'effervescent strands of hair' and endless descriptors of 'elegant but firm and precise movement' and so on for dropping a freakin' sugar cube in tea or some shit. Especially when it is purely masturbatory and got fuck all to do with the rest of the channel.
Now, if there is nothing of substance going on in the channel, then it's a different matter entirely. Fuck it, go nuts. Just try to make it somewhat interesting. This is when you can freeform all kinds of nonsense and maybe get something going that spurs activity and content.
In the end, I'll just repeat the beginning: Keep the medium in mind, both the IC and OOC one. It's a chat channel. It can be enriched by sporadic additions of minor flavor, but in the end utilizing it within its mechanical limitations will provide the best, richest and most effective user experience for everyone.
We have so many other tools at our disposal that can be used for 'support', and that's often where the 'effort' comes in. Write some fiction about your character that adds details which'll paint the picture behind the text in the channel, for those that read it. Have a character description somewhere (char bio, or linked in char bio is a good choice), that adds details to the character portraits users default to visualizing. If you've got character art, link it there.
And remember, if the visual representation of the character is the most interesting part of it, you dun fucked up. A force of personality and what they say and do is vastly more interesting than what they look like and how they do it.