So to get started, have a look at the shops in Varrock Square.
Buy the following items: Iron Scimitar, Rune Scimitar, Dragon Scimitar, Armour and some Food and Pots
Now go to your spellbook under the "Monster Teleport" and click on Rock Crabs.
Kill the Rock Crabs until you reach atleast 70-80 Strength, Attack and Defence.
Now for 70-80 to 99, i would recommend training your Slayer stat while training Combat
This will get you good money and max Combat Stats in no time!
Hope this helped.