A good description involves more than one sense. Don't just describe how it looks. How does it smell? Is there a particular kind of background noise? Is it cold or hot, dry or clammy?
A good description does not tell me how I feel or think, but is written in such a way as to lead me to freely feel or think a particular way. The description should not attempt to remove my free will; it should let me draw my own conclusions. The art of good writing lies in crafting your prose such that the conclusions that I freely draw will be the conclusions you wish to have me make. For example, don't say "The room makes you feel vaguely uneasy." Good writing requires that you provide concrete details within the description that would naturally lead a reasonable person to feel vaguely uneasy if they visited such a room in real life. Otherwise you will get a reaction in the vein of 'How do you know how I feel or what I think? You've given me no reason to make me feel that way or think that thing.' And the illusion of a place you've been trying to weave will be shattered.
Separate the mechanics of the room from the description of the room. If you've programmed some interactive verbs that you want to tell players about, set the help_msg for the room with instructions for their use. Or modify enterfunc to tell the player just when they come in. Or make a detail, such as a plaque, that has the necessary information.
Correct your spelling and grammar. Spelling errors are terribly discordant. An extra five minutes with a dictionary looking up the spelling of unfamiliar words will prevent the discordant shock of seeing a description of 'tappestries' in a room that would otherwise succeed in transporting the reader into your own personal vision of a place. The same is true of grammatical errors. Every MOO I've visited is full of rooms that misuse its/it's and there/their/they're. Remember: the only time there is an apostrophe between 'it' and 's' is when 'it's' is short for 'it is'. When you are using 'it' in the possessive sense, there is no apostrophe: 'its'. Furthermore, 'their' is always spelled with 'e' before 'i', and is only used when you are talking about something that 'they' possess. 'There' is a word referring to a location, and 'they're' is short for 'they are'.
If you want a concrete example of these tips, check out the tutorial.