First, yes it's hard to get a good group going at any level cause you really ahve no idea what type of player ur going to invite until ur first battle.
If I'm leader of the group, I'll go through the following strategy discussion before starting.
1) Assign main tank
2) Assign main healer (if more than one)
3) HAve one person call the mob and be the "leader"
ie. If I'm leader I like to do it cause I know I won't mess it up much, if at all.
4) Set way to call mob, and pull. ie. In my groups, I hail what I want pulled... go to spot I want it pulled to, and say, pull to here. Now there are hopefully some givens but doesn't hurt to explain, that only the tank goes and grabs the mob, and everyone else stays behind where I am standing, waiting for the pulled mob.
At time I will change this up a bit... normally once an aggro is pulled, the group will move to where or really close to the spot where the aggro was originally standing, cause you just killed the pop, rare will something pop on u again so quickly. However there are times that isn't the best. For example, in Thundering Steppes, fighting through giant valley, near T$ and over bridge.. there is a group of 4 aggro giants, no up arrows... but u dont want to pull them to where last aggro was, you want to send tank in, hitting them right where they stand... if you ever go there, you'll understand why.
5) Tank pulls to where I am standing, even a bit further since I am ranger and need to end up behind the enemy.
6) Everyone comes in and starts hammering away, avoiding any other aggros, and watching each other's backs for pops.
7) Once done, rinse, repeat.
After a short while all you have to do is say pull to here, and the tank will know what u want pulled (which is usually open ended and whatever is easiest or safest for him to pull) and everyone will get the hang of it.
As far as HO's go, make a macro or make sure whoever is going to be main trigger (scout types best at trigger, yields greatest variey of possiblities) and say "HO starting in 3 seconds" for example. Everyone shoulds top hitting specials, and then start triggering ho. Now I've rarely gotten this to actally work in a new group cause most people just don't get the value of ho's. Which is fine cause in most cases, you don't NEED them, but using them prevents overusing your mana, maximizing your xp in shorter time spurts. The best way to get HO's to actually make an impact is to work with the same or alot of the same people all the time and study (yes, study) the different possibliites and combo's of HO's, cause there's a ton of different possiblites, and some combos yield the best ho's. I have yet to take this step cause I hate studying but I'm sure it'd come in useful if I eventually did. Plus, I rarely am in the same group on a day to day basis.
Of course, there's always at least one who says, why so much planning, ur power hungry, blah blah so I try to start out saying, I'm not trying to be a **** but if we use this strategy there is a very very low chance we will ever die, removing the debt factor. Stick to it and well be fine. Still, some will complain, depending on how patient you are, keep em and let them see for themselves or boot them. One bad apple can spoil the bunch.
With this strategy I rarely die, probably a 100-200 :1 kill to death ratio but usually I or someone will die because they accidentally use AOE spell or accidentally targeted wrong mob. Which is fine, cause overall the team does awesome. For all you guys who are **** about debt, one death from someone else in your group can be taken care of in less than five minutes. Leave the person alone and dont yell or ***** at them. Be nice. :P
Disclaimer: This is a great way that I get my groups to work and work well. This is not the only way to do it. There are many ways. The key is to remain consistent, don't get overagressive, be patient, and pull one at a time if they are yellow+. This system may not work for you cause it's too "planned" or "repetitive" or "unexciting" (which I don't think so but some do). That's fine cause it's not kamkiaze style in any way whatsoever, cause I don't like dying alot and building debt. It's just a way to minimize deaths and blow through mobs once you get it going right.