"-CH" OR "-SH" WORDS
This is the one I see people mess up the most. You'll often see people writing poses that to them, work perfectly (i.e 'You push JimBaka'), but to you and everyone else, doesn't look quite right (i.e 'JoeBaka pushs Jimbaka').
To work around this, whenever you use an action is a pose that's going to be prefixed with a '.', if it ends with 'sh', 'ch', or the letter 'h' in general, always stick an 'e' after it, because the MOO doesn't know to do that on it's own. For example, the example I gave earlier would be fixed by doing it like this: .pushe jimbaka. While this won't look perfect to you, it will to everyone else.
This one's a little more complicated, and even I don't know exactly what causes the pose target to change, but this is what works the most for me:
In a particularly complex pose, there's going to be a lot of 'me', 'my', 'his', 'her', 'they', etc being thrown around. This tends to confuse the pose system, and changes who the pose is actually "targetting". What I've found is usually the pose'll work fine, but when you use something like 'me', 'my', or less frequently 'I', you'll have to refer to the other person by name the next time you mention them in the pose, instead of using their pronouns. If you do use their pronouns, the pose will still be targetting you, as the 'me' you wrote switched the target from them to you. Using their name switches the target back to them, and you can use their pronouns from there on out like usual.
Sometimes when you use a pose, the punctuation in the middle of it will disappear at certain points. This is usually if you do things like a comma or period after using the words "me", "my", "I", "myself", etc, or any other player's name or pronouns. The only way I know of avoiding this so far is to just not stick your punctuation immediately after those words.
This one's pretty simple, but I've seen enough people that don't know about it that I thought I'd give it its own thing. If you want to start a pose with an adverb, or anything that isn't going to end in "-s", use the "pose" command instead of just a period. For example, "pose quietly .cackle to myself as JimBaka is pushed".
There's probably a few things I've missed, so feel free to call me an idiot loser dumbfuck in the replies if it was anything very obvious.