Question on macro's and handling non-same class teams

[Khatovar]

And 2nd, How would I arrange my team? I don't want my caster to... follow my warrior after he charges to an enemy. I understand I can just break follow, but that requires me to switch to the slave press a key, then switch back, between each pull

As aasi888 says, you can use arrow keys. I do not unbind the arrows in my keybindings menu, it isn't necessary with most key broadcasters as you can configure ones like ISBoxer and HotKeyNet to send keypresses to only certain windows. This is something I take advantage of to move slaves individually by setting up a mouseover region in HotKeyNet over my Jamba Team List. This way I can put my mouse over a name in the team list, press any movement key and only that slave will move. I also like to still be able to use the arrow keys for travel to push everyone over phase lines, which are notorious for breaking follow and causing you to lose slaves.

For breaking follow, I am set up to send the strafe keys {Q, E} to slaves as well as my main. When I'm ready to pull, I just tap one of the strafe keys while running forward and the slaves step left or right and that breaks follow, assuming you aren't using Jamba's strobe follow. Follow strobing requires that you first turn off follow strobing, then break movement, otherwise the slave will just refollow. There are times where strobing is useful in dungeons, but for the most part, I only use strobing for mounted travel.

[Bettysue]

The biggest tip I can give when starting out is get ready to be frustrated with quirky mechanics ie vehicles, ground clicking, rotations, as they are applied to boxing. All have workarounds so do as you did in this case read and ask direct questions. Make sure you explain what setup you have, what you are seeing and what you expect to see. We don't sit at your computer so it's quite impossible to know exactly what's going on.

Broad topics like I have a tank and a healer how do I beat the big snake boss? ...will yield exactly the thread you have here. Something like:
I use HKN and my pally tank refuses to use his shield on the big snake boss, "/kill snake with shield" is the macro I'm using where did I go wrong?
will get you in touch with the right people to help with your specific dilemma.

We also are not you, asking our opinion means you will get it, don't be upset if it doesn't jive with your opinion. Typically this means you provided too little information... as you did in your OP. There are loads of tanks and casters, all have good and bad aspects, at level 15 anything with a little facerolling works, do you plan on raiding, or are you looking to level some tradeskill mules? The "best" will change quite a bit.

I would make up the statistic that 90+% of the guides provided here are taken directly from how the writer actually does it. Khatovar has made several excellent guides for HKN and even states that she uses the techniques presented in them. MiRai has made literal click by click videos for how to setup nearly everything in ISBoxer, and does quite a bit to provide public assistance to those with specific questions.

You are in luck because MiRai has posted a link to Khatovar's guide just a little above this post.

All that being said, my opinion, based on the little information you provided is as follows:
Since you mentioned priority macros I assume you know how to set them up with whichever class you choose. For your tank combining "interact with target" (IWT) and the "click-to-move" mechanic will cause them to run to their target, simply add the keys to your priority setup using the "key-up/key-down" mechanic available in nearly every boxing software. Your casters/ranged are easiest to lead with during a fight if you use the above setup for your tank, just unbind movement keys on the tank and use arrows or even "click-to-move" to position as needed.
Having some sort of toggle for IWT means you can control the tank and keep them from spinning wildly around the target. I personally use Hotkeynet (HKN) and have a key to toggle a variable for whether or not my melee should spam their IWT keys. This can also be done in ISBoxer, but I will have to leave the details on how to the more experienced, however, it is quite well documented here and on the ISBoxer site.

Using a priorty setup means you can macro or approximate timings for most procs, and can essentially reduce every class down to 1 button mashing for decent effectiveness. After trying different things out while levelling you can tweak and add to your setup for maximum (boxed is not necessarily perfect) effectiveness.

Tank-wise Pally's and DK's are quite easy to macro. For example priority macros on a pally work well because the majority of their procs only fire if available, meaning they won't stand and hard cast something when the proc would have made it instant. Working out the timing for their holy power abilities is tough to perfect but can be done with a little effort and checking logs. PvE can be mastered on target dummies, then adjusted a little for movement and dynamic targets in dungeons.

[Pazgaz]

You are asking questions about setting up things and don't want to check the guides explaining how to check up things?
Anyway, a good starting point will be to tell us what kind of multiboxing software you are using.

[Khatovar]

Well, he says he read them. The Newbie Guides themselves aren't designed to be a step-by-step setup, they're supposed to be a starting point to understanding all the stuff that goes into multiboxing. Obviously everyone does things a little differently. The guides linked within the newbie's guides, however, are, which is why they're compiled there and broken up on a program by program basis.