I believe that, first foremost, you have to create rs 3 gold a throne room and then build a floor in the middle of it. You can also build an oubliette under it. It is also necessary to build a trap door inside. Then, there are two other ways of getting inside There is a big cave entrance in a garden/fancy garden. The stairs are a flight of stairs inside the room.
Once you've built one of these two you have the option to build a lower level room in the same way, but there should only be one option available for this. When you've constructed the room(s), you can build normally in construction mode, creating treasure rooms, dungeon hallways, intersections or any other room from above that you wish to have down below too.
If you've not completed the Love Story quest unlocks a different kind of dungeon which includes a plethora in new and exciting dungeon guards that you can add down there, such as scarabites, iron dragons, black demons etc. The majority of them are much less expensive than the old hellhounds, trolls dragons and so on.. If I've missed something, do not hesitate to ask once more.
Lardar pretty much summarized the most effective methods, however for a good plan we'd need to know precisely what your level is.
Good luck! It's entirely dependent on how you'd like to approach it Personally, I'm not keen on running and don't need the money, which is why I keep slaying at the minute for the effigies I can use for runecrafting. In addition, I am helping people to get their RC and effigies (91 from now, I'd highly recommend this because it's a no-cost 30k rc XP a day)
I'd use the penguins as well for a fast boost every other week, because it will all add up leading to a high number of XP over the course of time it takes to finish 99 Runecrafting. If free trade returns, we'll see the increase of Air, Law and Double nature running again, so that might be the better option to simply be at your altar for all day long and let others be the source of essence to you.
I'm planning to camp in avies soon.my stats are 73 range/80 Def/60 pray. Should I go with the tank method? if so what should i wear? Should i just wear my current range armour? (full range of armadyls, snakskin boot the zamorak blessed dhide dhide vamps, ava's accumelatour ammy of running, rune bow, broad bolts God book.
The Granite shield is very effective as it provides a very wide defence range... What do you think? should I wear monk's robes and a high prayer bonus and cheap RS gold keep praying all day? I'm wearing exlibtur in spec (or what you call it) Is there a better option? (don't say enchanted version , i do not want to pay 10m on it)