Attack is a skill that is trained using melee. The higher your attack level is, the better weapons you can wear and the more accurate your attacks will be.
1 - 40: Train on Barbarian Women at ::train or ::train2
40 - 80: Train on the monsters at ::raresmini
80 - 100: Train on dwarfs at ::train (bring food if they are fighting back)
100 - 120: Train on Jogres at ::train (bring food if they are fighting back)
120 - 150: Train on guards at ::train2 (bring food if they are fighting back)
150 - 175: Train at the guys at ::barrows (bring food if they are fighting back)
175 - 200: Train at the minigame at the general store at ::train
Note: These are just suggestions and attack does not have to be trained this way.
These are some decent weapons to use for training.
1 - 60: Use the abyssal whip you started out with
60 - 80: Use a dragon scimitar
80+ : Use a gadderhammer