This really depends on your level. For lower levels I would recommend rock crabs at level 10 and with 50 hitpoints these are great xp as they have poor attack strength and defence. They are P2P. As a low leveled non member I would suggest dummys in varrock to get you to 10 attack then train on men for a bit before going on to harder stuff such as minotaurs and goblins in the stronghold of security. For a high leveled member, Ape attol is a great place to train as the creatures can't hit through prayer inside the temple and have very high hitpoints. They will heal themselves at 25 hp so you can get more xp with less clicking, faster xp. For a non member deadly red spiders can be attacked in the 3rd level of the stronghold of security. You require at least 50 defence to make this trip even slightly worthwhile. For both members and non members, a fun way to train is at duel arena if you wear no armour you can use prayer continuously and members always have there spec recharged. Soul Wars and Pest Control are minigames that give great XP rewards for members.