World of Warcraft®

How can I improve my Paladin?
Other than gear, could I benefit from having other gems than the ones I'm currently using? Reforging? Enchantments?

First thing I noticed: your dodge and parry are waaaay unequal. You want to lower the amount of parry you have and/or increase your dodge so that they are roughly equal to each other to avoid diminishing returns.
You might want to swap your Scale of Life for a trinket with mastery as its main stat (such as the valor point trinket), as this will help you get avoidance cap.
Avoidance cap is 102.4%, you work it out by adding together your dodge% + parry% +block% +5%. If you are below 102.4% you are not capped, if you are over it then every attack you take will be dodged, parried or blocked. From your reforging I can see you already reforge for mastery, which is good.

For your glyphs, dazing shield and holy wrath are pretty nice major glyphs. As a paladin you shouldn't have trouble with your mana so get rid of the reduced mana cost on crusader strike and find something more useful :)

Other than those points your gemming/reforging/enchanting looks perfectly fine to me.

I'd suggest you to put some of the green gems to blue sockets and not to use blue stamina gems at all (unless some raid/dungeon encounters require more stamina instead of high block chance, I don't know about this). At skill level 500 of Jewelcrafting you can learn to craft for example Fractured Chimera's Eye.

Looks good enough for dungeons, lfr and normal ds.