You can get away without using a prepared scenario in Maid RPG, at least at first. Have the Master give some arbitrary orders, roll on the random events chart, and watch the players scramble for Favor points in the resulting chaos.
To make a scenario, you essentially want three things:
- A problem or situation that can't be resolved in a single encounter
- A planned series of encounters, events or tasks for the situation, in which the player characters will have to compete and/or work together to earn the Master's favour
- Some sort of new custom game mechanic for the scenario, to keep things interesting
You can draw scenario ideas from anime or other fiction or non-fiction sources. Hayate the Combat Butler is good inspiration for Maid RPG: it's an extremely wacky anime about a spoiled rich girl and her staff of butlers and maids. Pretty much anything can inspire a Maid RPG scenario, considering that one of the random encounters is "mansion blasts into space and the setting changes to sci-fi."