Hi there!
Me and my friend started leveling with RAF two days ago and in this thread I'll explain how we did it and also a commented video of the last instance we did, Scholomance.
What do I need for this guide?
First off you need a character that is capable of boosting. For the first instance, DM, any class with a decent AOE ability will work. However for that latter part of this guide you might need a class that also is able to take some beating.

Secondly you and your friend needs to have 3 accounts combined.
First account is the boosting account.
Second is the recruiting account.
And the third is the recruited account.
To be able to go all the way to 60 you need to buy WoW Classic for the third account otherwise you can't go past lvl 20.
I also recommend having a decent high level char on the second account. This is good because then you can go to the instance you're about to do with that char and summon the char from the third account and then that char will be able to summon your low lvl to the instance and voila, both low lvls are there.

Now to how we did it. We did it with the 5 following steps:
Step 1, 1-10
Create level 1's on the second and third account, group up and then just level like you would a normal level 1. Really isn't anything more to say here, You should be level 10 after the first batch of quests in your second hub (Goldshire/Kharanos etc).
Note: I followed Zygor's Guide for this step

Step 2, 10-20
Time for the first instance, Deadmines. What we did was to run with my main on the second account to the instance before we started to lvl so now I only had to log in and join the group and I can summon the char from the third account. When you have done that log onto the char you're leveling again and the third account can summon you.
In this instance we used a rogue as boosting class and it worked really well. However I do recomend using a priest specced into Divine Aegis, it is by far the best class I've boosted with in here due to the shield you get when you critically heal someone. With a priest you can have your low lvl chars following you and they will pull what needs to be pulled due to their huge aggrorange. When the mobs get close use Holy Nova to kill them and heal your team.
We basically just run through the entire instance however when we get to the boat we run with the Booster on the left side of the boat (towards Cookie) all the way around to the ramp up towards Van Cleef, run up and pull Van Cleef and then jump down to where Mr. Smite used to stand and wait for all the mobs to come down (they will pull all the mobs you didn't on the right side of the boat).
Nuke everything down and then run back to the start. We run back in the instance, not outside it's faster and easier be aware of the patrols that have spawned though.

Step 3, 20-40
Scarlet Monastery. You all know it. We used the Rogue as booster here again. Run to the instance with your high lvl on the second account and summon the third account, just like in Step 2.
The 4 SM instances are short and fast, so you might think "I will do Cathedral in like 5 mins and I will only be able to do 5 every hour so I will have 35/60 min downtime in an hour" but that is not true. All the SM instances are the same instance reset so to speak. If you do all 4 instances and then reset it only counts as 1 instance towards those 5/hour.
In light of this try to find a rotation that takes about 12minutes to complete. We did Cathedral and Armory and it took about 10-11 mins I think so we only had a little downtime each hour.
In Cathedral we did it in 3 pulls.
First pull is the entire lower garden. We popped sprint and pulled it all and nuked it down.
Second pull is the upper garden, no sprint here so we just ran and pulled while spamming FoK (= No big pull, everything dies while we run).
And the third and last pull is the entire Cathedral itself. This pull is real easy to do, just go in and attack the boss and everyone in the cathedral will run to you. Nuke it down and then go out and into;
Armory. This we did similiar to the second pull in cathedral, we just ran with booster spamming FoK as we ran so the mobs die eventually. No special pull here, just run through it and AOE while you go.

Step 4, 40-45
Zul'Farrak. Go to Tanaris with your main and summon. There are 3 quests that you can take in Tanaris and those are: Divino-matic Rod, Scarab Shells and Troll Temper. Take these and then head to the instance with the booster guarding you while you run.
In here we changed from Rogue to Prot Pala as boosting class.
What sucks now is that they have added a Dismounting Shout to the mobs in this instance and due to that we only did 5 levels here.
Anyways start by running in with your boosted and pulling all the mobs you see. Take as much as you know you can handle and then nuke them down. Beware of Hex! If your booster gets Hexed and your low lvls are too close the mobs will aggro them. A lot of casters in this instance so Line of Sight is important to make them get close to you.
Go to the right and towards the pyramid event. On the way there in the room with a lot of scarabs kill them. Might not seem worth it since they're not elite but there are a lot and they die really fast.
In the next room, with all the graves, if you can handle it click all the graves at once and then nuke down. Don't be cocky here, it's A LOT of mobs. Take as many as you can handle and nuke.
Then clear the pyramid area and then do the event (You only do the event ONCE for the quest).
When the event is completed go towards the Gahz'Rilla "room" and clear it. Then run towards the exit, but not the way you came in, go the way where there still are mobs.
Rinse repeat to lvl 44/45. The 3 quests you made give roughly 25k exp each with RAF.



Step 5, 45-60
Scholomance. This instance is REALLY good for boosting, by far the best of all the instances in this guide at least. Mobs are tightly packed and best of all, the instance is small and with the new changes in 3.2 to how long range you get exp from, your low lvls can stand at the entrance the entire run.
For this step I made a video on how I did it. The video includes commentary with a few tips and pointers. Enjoy!

EDIT: I forgot, make sure the third account hit lvl 60 first, then get the second account to 59,99 and then grant the last lvl and you will basically be lvl 61.
And also, you can grant 29 more levels (Right? Not sure about this >.

› See More: [How To] Boost 1-60 with RAF