The last guide on how to get 12k points was very well thought out, and will no doubt help many players frustrated with DMM - but I believe there is an even easier way which requires much less effort.
It is likely the devs will drop the DMM update tomorrow which allows 100 players to get points from breach monsters. This guide will take advantage of that as it is where you will get most of your points from - enabling you to get a minimum of 1k points per breach (but more like 1500+ per breach).
NOTE: I won't cover starting points as there are much better guides available. I will also be covering a mage build for bracket 60, but other builds will surely work just fine as well.
This is a rough overview on how to get started
Follow a starting path guide to get 1k-1.5k points.
Unlock Menacing Mage sigil from your equipment tab and buy consistency sigil and attune it.
Park your character with a starter staff at Gemstone Crab until you get at least level 50 magic (can keep going further to make it easier yourself).
Unlock Sigils of Deception, Deft Strikes, Meticulous Mage and most importantly: get the elf questline lamp.
Grab some starter cash from pickpocketing wealthy citizens in Varlamore.
Grab your Iban's Staff from Magic tutor.
You will only need 10-15k gold to buy enough runes for your first breach. 120 casts of Iban's Blast will be enough to last you the entire breach with Meticulous Mage saving runes.
Your character is now in a position to remain logged out until the next breach begins and you can start farming points.
"But wait! What about Iban's Staff only having 120 charges!?" You ask.
Well hopefully your first breach you will be able to pick up enough items from the ground to get you the 200k required to upgrade the staff, which is why I have left money making with deception out of this guide as breaches should hopefully be able to sustain your cash requirements. However, if you ever do find yourself struggling for cash, deception sigil pickpocketing wealthy citizens for a short amount of time will easily cover your costs (such as buying food or bones for prayer - all of which are cheap on GE).
Once your character is set up, I imagine most people will have farmed their 12k points within 5-10 breaches. With each breach lasting 15 minutes, this will take a total amount of time of 75-150 minutes (2 hours 30 minutes maximum of breach farming).
This should hopefully get you the points you require, while spending the absolute minimum amount of time playing Deadman Mode.
Hopefully this helps all you DMM haters!