In my experience, I seem to get more comms when I'm playing AST compared to BRD (since people tend to comm tanks or healers, and just ignore us DPS v.v). I usually don't care too much about commendations; the only time I get salty is when I am consistently having to raise party members (this is usually in my Dun Scaith runs), where I'm literally the only party member not dying, where I'm sharing Balances among DPS if I'm holding a Balance already, and don't draw a Spire/Ewer to spread it but instead a second Balance, and basically just being a god (no, I am not trying to sound or be arrogant here), and walk away with one or no comms. That's the only time I get mad about commendations, but usually that anger only lasts for about five minutes.

I comm for different reasons, and I tend to comm other DPS if I notice that they are doing more than just hitting 1-2-3.

If I see a BRD playing me Foe's while I'm DPSing on AST, they automatically get my comm. Same if I see them pop MP song for myself if I'm running low, or TP song for some of the TP-starved melee without anyone having to ask for MP/TP. Plus, I'm partial to BRD anyways since it's my main, and if I see a good BRD, they're more deserving of my comm than a tank or healer, who usually just get brownie points for showing up, imo.

If the DPS suck, I'll comm the tank if they did a decent job holding aggro, and if they knew what cooldowns were and how to properly use them. Bonus points if they're a DRK that consistently keep up BOTH Grit and Darkside during the majority of pulls.

If I'm running 8-man or 24-man content, and I have an amazing co-healer, I usually comm them, especially if they are another AST, and coordinate card usage and sects with me.

If the entire group was just subpar, I don't comm anyone. If I feel like throwing them a pity bone, I'll comm whoever died the least.

However, sometimes I comm people that others would think probably don't deserve comms. If I am running something with a sprout, and I can tell that they are trying really hard to do well, even if they die a lot or don't have the best DPS or rotation, I still comm them because at least they are trying. Bonus points if they're given advice from another party member, and take said advice to heart.

Sometimes I comm a person who I think is funny, or who makes the run less boring. Sometimes I comm someone if they use a funny macro. And sometimes I comm on things like character name or glamour.

Commendations are more or less subjective, so I don't hold them to much value usually. If your lack of comms seems to be a consistent and pervasive thing, however, I would take a few moments to look back on your individual performance in duties, and see if there is anything you think you can do to improve. Just keep in mind that there are those that just don't comm at all, or only comm 5 times a week to get the Challenge Log entry.

Side note for myself (and this goes for some people I know as well): I don't care how well a player is doing, or how god-like they are, the minute they post some "Thank you for the party! If you liked me, give me your commendation! I almost have XXXX comms!" macro, they automatically lose my comm. Commendation begging just annoys me more than someone outright sucking at their role.