Recently my classes started falling behind on levels, I am lvl 57 with 56 mage, 47 illu, 51 shaman. My other classses are very low level and I want these 3 classes to catch up with me. I am not sure what to do to get CP. I run daily limited but they only give like 30% of a level and finding trials is very hard since most of the runs fail or there's hardly any 1 running 55+ trials.

Can someone please help me and give me some info on how I can level my classes quicker

Do you use the prof Koss bonus from aven? For lvls 51-59 it gives 50% extra cp you could also hand in 10 of a regions fame item to get another 30% boost which will stack. Do your limited dungeons twice - which ones do you do?
I started grinding at lvl 53 just because; I got nice cp running temple and crimson mobs although you would only get 60% as a lvl 57 so do any limiteds that give decent cp - I hear crimson is nice and farmable at that.
I think that illu will be hardest to lvl in limiteds cos it doesnt have spamable aoes so go into the 3v3 arena as the illu - even if you lose you'll get cp and illus are really good at pvp. Mage is your highest class and it would also be the easiest to farm with in limiteds althou sham would be good as welljust not as fast but it has heal.
There is also Monster battle arena which is not class dependent to you can pretty much lvl anything there.

How to level your classes faster?:

-Complete all your limited dungeons within 5 levels of your classes
-Purchase or run Delphi Temple (first room). You can level almost all the classes that have at least one aoe with the exception of warlock. Just stack movement speed items + HoT items and whether or not you are geared will not matter as much, though it will take longer than a geared person.
-Purchase Manor DGN runs or run Manor using bard and engi. Again this can be done by stacking lots of movement speed gears or HoT items.
-Purchase Venin Trial runs. Again, you can run this yourself using bard and engi.
-Go to trials if possible

A note to add is that you should make use of the boosts available to you.
-Professor Koss in Aven
-<Tarrot Card Reader> Morlin in Aven gives you a 10% CP boost
-the Christmas NPC, Ganache gives you a boost of 5% exp, cp and move speed for 3hrs via turning in 3 anger tokens.
-Also when doing runs, using charms (auric, iris, cp charms) can help you level faster