I did some tests for the single-player campaign mode and I’ve managed to reach Gold tier, position 790 on a very crowded realm. I need to beat only 30 players to get to the Diamond league.
I’m at the first map from “Avenging Moria” campaign.
Here is what you need to do to get a higher score and reach higher tiers etc:
Train Tier 3 and Tier 2. As many as you can.
Revisit the old maps and attack each location (not only the last location from each map). This time, use 3/4 of your troops as Tier 3 and Tier 2 (depending on what you have) and around 20-30-40k troops from Tier 1.
The enemies will attack your Tier 1 troops first and you won’t lose any Tier 2 or Tier 3, so no major might loss.
As your attacks are more efficient this way, you will get better scores for each location and this will increase your rank and you will go up in the top, reach even Diamond Tier.
I attack with 100k troops (level 10 Muster Field).
Don’t forget to use attack/hp runes and your highest level hero.
Notice that both campaigns, “Clearing the High Pass” and “Avenging Moria” share the same top charts.