In the past i would always advise building up a dragon team first, since that is where you get your gear from.

However with forge gear being so good it may be worth building your faction war teams, depending on your roster.

A good step may be to post your roster.

Ninja 3/6*  Level 60

Kael 5/5* Level 50

Elhain 4/5* Level 50

Judge 0/4*  Level 40

Jarang 0/4* Level 21

MuckStalker 0/4* Level 1

Icebound Prospector 2/3* Level 20

I have a couple of 2* that are just sitting there plus the Mystery Shards that I can use too.

I just realised that I am Water logged in champions.  This is bad. I need a varity of champions.  This might be why I cannot move through the towers/dungeons. 

Number one rule of this game - don't waste resources. Ever. And that means don't start leveling garbage champs just because you have them. That goes for Judge, Jarang, and Muckstalker. Icebound you can level as food.

Get Kael to level 60, since you'll use him as your campaign farmer. Then, just farm food, and only use shards during summon events, and even then, don't waste them just whenever.

How do I tell which champions are the ones to level up and which ones not to waste resources on?  I thought it was the ones with the symbols in the upper right hand corner of their pictures  but I guess not. 

The short answer is "experience". The longer answer is, go check out guides. Hellhades, Ayumilove, etc. They'll give you an idea of who is useful and who isn't.