To get quickly increase your Alteration skill, make sure you have these spells: Open Average Lock, Open Easy Lock, and Open Very Easy Lock. Then, find a chest that you would normaly need a key or have to lockpick. Use the opposite spell of the chest. For example, if the chest requires the easy spell, use the very easy spell on it. Make sure you have some Magicka potions or you can just wait an hour every time you exhaust your Magicka supply. In a short period of time you will have leveled your Alteration skill dramaticaly.