There is a difference, though, between masquerade performances done for the sake of competition, and being hired to perform in a show (as is what it seems is done in Norway? Perhaps other countries?).
Most of the tips here about entertaining the audience are fairly universal, but if you're being paid to entertain the crowd by the con, and they chose you because you're good performers with good costumes, then do what you think the audience will really enjoy and it doesn't matter if it's comedy or drama, action, dance, or anything in between. What's at stake is merely their enjoyment, and possibly the option of being hired by the con again in future years. It's not the same as over here in the States where performances are being done in competition, for the sake of winning awards as well as being artful and interesting and entertaining to the audience. So there are some differences.
Founder and Vice-President, Madison Area Costuming Society, a chapter of the International Costumer's Guild
Strange Land Costuming - www.strangelandcostumes.com