Save your game in Maple Story Mesos a few files. Every now and then, save it in another one. For some games, especially JRPGs with branching routes, you might want to go back to a key point in the game and make a different decision. If you only save in one slot, you will have to start the game over in order to get back to that spot.
Make use of parent control settings on MapleStory 2. You may want to see if this game can be played online. If it is, limit the time or turn off the wireless so they can't access it. You should also verify their friend requests and make sure they do not play excessively.
Many modern online games give you two choices. First, you can earn in-game content and rewards gradually through investment of your time and work. Or, you can just flat out buy them with your real world money. Look over all the benefits that are being offered before you make a purchase. On MS2 Mesos one hand be sure that you are getting your moneys worth with your purchases. Some of these offers, however, can save you many hours of level grinding.
Keep a cap on the total time you game in a day. Gaming, like anything else, can turn into an addiction. This is something you must watch out for. Try to play no more than two to three hours every day. If you do play for longer, be sure to take regular breaks.