Originally Posted by Spacecadett

To start with, I've examined your Shannox parse only, bearing in mind that it's the one involving minimum movement compared to the other 6 encounters, also enabling you to keep your eyes on the boss only and not worrying about external sources of damage (at least not that much). Some things that came in mind at a quick glance:

1. As with most retri paladins, you need to work mostly on your CS. Log shows 1 CS every 6 seconds, while it should be 1 CS at every 4.5 seconds (latency included). Make sure you're not giving up on CS for any proc, it should be used on cooldown, and even more, "spammed" on cooldown, as shown by Exemplar.
2. You're running with pretty low mastery, considering the actual magnitude of this stat. With better gear, you should be able to accumulate more mastery, but generally, the rule of thumb is to go for your hit and expertise caps (which you missed somehow) and then reforge every other stat into mastery.
3.Your Inquisition uptime is very low. Log shows an approximate 76.9% uptime, while it should be as close to 90-95% as possible. I strongly recommend that you read up again the Retribution thread on ways of maximizing your Inquisition uptime, as well as the Ret FCFS forum on ways of configuring the addon into helping you manage your Inquisition.

To conclude:
It's, sadly, no wonder that you are not performing to the maximum of your expectations. (1), (2) and (3) combined give us an under-performing paladin. In simpler words: Less CS = Less TV = Less Inq = Less HoL = Less DPS.
For more info, consult the above posts of your fellow paladins, containing useful tips and advices as well some extra theorycrafting from thread authors and high-end raiders. All the best for your raiding endeavors!