I'll just write a really quick guide. I personally suggest using a whip if you want to level up Attack and Defence. You should however use a Saradomin Sword if you'd like to level up Strength. The best thing to use however is a Chaotic Longsword or Rapier if you have one.
As for the locations, here are some great training spots:
Skeletons: Located at Ape Atoll --- Requires you to start Monkey Madness
Bandits: Located south of Al Kharid at the Bandit Camp --- No requirements
Armored Zombies - Located at the Altar on the Eastern side of the wilderness --- Quest required (Sorry, Forgot)
I hope this helps, took me a while to think it out