Just be careful where you get MQ2 from. Most builds are ok, and only contain normal plugins. The ones to avoid are the ones that tell you they allow you to warp or edit memory. Even with a safe build, you can still fall foul with macros though.
/plugin list
will show you what plugins you currently have installed. You can then google them to find out all about them. eg. mq2cast allows you to cast an item/spell by issuing /casting "Greater Heal" gem|1 This would cast the spell greater heal, from gem slot 1 and mem it to gem slot 1 if not allready there. Google will fill you in on the most used plugins.
Mq2hud is a pluign that allows you to display information on the screen (eg any detrimental effects that you have on you)
Mq2netbots allows you to send command to other toons. If unsure google it first. The GM's are putting a lot of trust into the community by allowing MQ2 for boxing (/stick, /bccmd etc etc) so just use common sense when using it.
Having a hot button that tells your toon to cast a spell using netbots is a great way of boxing. Warping around the place is a quick way to get banned.
mq2melee has its uses, but also has its issues. As you found out when you attack a mob. You can read up on the plugin and customize it for your toon, or switch it off. Mainly use common sense, and if you dont know what your doing google it

I'v heard Firenze dosent use MQ2, but he employs a team of children and he just shouts at them to press buttons.