Prestige after all buildings are maxed without using coins

What are the best ways to gain prestige after you have upgraded all of your buildings to max without using any coins if you don't have the money to buy them?

Start building your army, scouting nearby cities to see if anyone has left out troops, and upgrade turrets.

Get like 10k cavs (just an example) and start farming people, first build 599 cavs, then 249 cats, then use rest on archers or inf (if you aren't building defenses). Do this in each city, just dispatch your cavs to each city until you are done.

Repeat this, somedays you'll find some prestige out and be able to take him!

If you can't manage the crop output, simply send the unneeded troops to a level 9/10 fortified point.

Get a good army, farm forts and mass train archers (best resource/prestige value), and make sure to keep an eye open for careless neighbors.

[Backburner]

Fort farming and pump army, max your training slot, actively farm forts and make sure you have at least 2 groups of units training at the same time. If you don't take resources into consideration then cats and horses are the best to train since they're the fastest to finish.

At the end of the day, if you don't have coins then high level is a highly repetitive and boring experience. The prestige you gain from training troops decrease as your level increase so by level 16+ you will find yourself repeat the same process but with very little gain and even if you're ultra active about this it will still be very difficult to compete for rankings against people with coins.