-To get quick levels in the Alteration skill, make sure you have the following spells: Open Average Lock, Open Easy Lock, and Open Very Easy Lock. Then, find a chest that you would usually need a key or have to lock pick. 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 simply wait an hour every time you exhaust you Magicka supply. In no time you will have leveled your Alteration skill dramatically.
-When you get the Open Very Easy Lock spell, use it on all boxes, barrels, and doors-- even if they are not locked. This will level up your Alteration skill quickly.
-Go to the Imperial City Market place at day and enter the shops. Make sure you have at least Open Easy Lock equipped. Go inside the shops and use the spell on the basement and living quarters doors, but do not enter them. Then, repeat in any other shops.
-Use the following trick for easy Alteration and Security experience. Note: You must have any locking spell. Find a door that is repeatedly out of sight and cast a locking spell on it. Then, unlock it with your lockpicks. Depending on your level, you will level up these skills two to three times a day (depending on level, amount of Magika, and lockpick quality).