-Inflict a decent amount of damage on a monster, then wait for someone else to kill it. When it dies, you will automatically get experience. While you are waiting, damage another monster.
-For easy experience until level 90, use this trick. Note: This method is not considered "training". To enjoy your Maple Story experience, it is recommended that you do not always use this method. This method is just for means of leveling up faster. Get max Three Snails, a beginner skill, and gather at least 1,000 Red Snail shells. Then, take the boat to Orbis, then the train to Ludibrium from there. Have a high leveled friend that can kill Vikings escort you to Warped Path of Time: IV. Stand in a location that is safe and have your friend lure Vikings there. You will not get hit if you selected a good location. Use Three Snails on the Vikings only once as he lures them to you. Your friend should then kill the Vikings after you have used Three Snails on them.. You will gain at least 900 experience with every Viking that you have snailed that your friend has killed, depending on your level. Note: This also works with Death Teddies, Master Death Teddies, and Grim Phantom Watches.
-Have a party of very high level warriors with Hyper Body with the Heal skill. If you use Heal you will get experience. Keep using Heal until the warrior's HP is full. Then, have them to right click the Hyper Body skill at the top right side. Repeat this as many times as desired.