There are many places you can use your character to fight with. Over time, he/she will get stronger and learn better moves. In this article, I will teach you how to speed up this process with little or no hassle.
Melee Users
The best place I would recommend is the Giant spiders (Lvl. 50) in the 3rd level stronghold of security (south of Edgeville, west of Varrock). The spiders there attack you automatically, so not only do you not have to press so many buttons, your hands can rest. For levels 50-60, this would be the best place to train, but if you are under lvl 70 combat, you should take a watch your health carefully. Recommended food to bring is salmon and up.
Next best place would be the lesser demons. If you have the combat lvl (55+), then this place is for you. Bring lobsters and start killing the lessers in Karamja, under the volcano. They have very low defense, and their drops can be rune med helms! A word of warning though, they do hit hard to high levels too (about 8s), so watch your health doing this as well.
The third place, fourth, and fifth place I would recommend is again, in barbarian village. The minotaurs (LVL 27!!!) and the zombies lvl 30, and the barbarians are all good people to train on for low lvls (25+). They don't require a lot of food, and they give great xp. If you want to stay there for a long time, bring trout or grab it from the people fishing nearby.
Mage
There is one place almost all mages go to: the lesser demon on the top of Wizard's Tower. It is in a cage, so it can't harm you. If you want really fast mage xp, its good to go with earth bolts. It's also good for archers, too, but you can't grab your arrows there without telekinetic grab.
Second, you can train in Fist of Guthix (see related article: fist of guthix strategies and tips [the first one on google search if you put in the title of the article]). Wear bronze armor and a staff and start firing away with your best spell, and this could get you a good mage level as well.
Range
You can basically train range anywhere. If you are a low level, start training on the Minotaurs (lvl 10), and you will gain lots of iron arrows to use. DON'T pick up your arrows if you want faster results. The barbarians in the beer place work too.
All Users
To top things off, I would recommend the lessers, barbarians, and the minotaurs (LVL 27!) for all types of attack. In the lesser demon area, there is a hiding place for range and mage, and same is with the minotaurs and barbarians.
***CLAN WARS INFO: If you want to be part of my clan, just add me: R Protoman
I am currently forming a big clan for reverant hunting, clan wars, and the new PvP worlds where you can fight literally everywhere you go. I'll post another article when I know we're good to go, including times, location, world, etc... I will probably allow only 65+, but you can try anyway and maybe I'll let pures under that level in too. Thanks!