EQ is no different from the other games around here, really. You have to continuously spam keys in combat in World of Warcraft, LOTRO, EQ2, etc.
The grand design we recommend is for you to set up one key for general spamming, and then a few additional keys for situational abilities. I have two DPS buttons that do largely the same thing, with the second one just going into "overdrive" (adding more abilities into the sequence). The DPS button can rotate between different abilities and such each time you press it, and depending on the game it can do something both when you press, and then when you release the button. You can manage different rotations for each class/role with the same button. (including healer) I've also got buttons set up that switch those DPS buttons between area and single targets. I don't know if EQ bards are still like they were when I played in Planes of Power and thereabouts, but twisting songs would easily fit into these rotations as well.
I also have a button for assist, and a button for follow. These are right next to my DPS button. I spam all 3 of them a lot. For situationals I have keys set up that group different classes abilities together -- a stun button, a manually-targeted AOE button, a crowd-control button (including round-robin), a panic button, a "blow all my cooldowns that give me extra dps" button, and so on.
Hitting buttons is to be expected during combat, the trick is to do it efficiently
As far as "lighting up trick" theres not much of a trick to it, it's just a light and doesn't affect anything. The Light Action only works on G11 and G15 keyboards, currently.