Get Athel to *6. You NEED a Campaign farmer to make more food for your champions. That is your top priority now. Athel is still my Campaign farmer at account level 71. She will help you a lot in early Arena, and in Dungeons too, especially Fire Knight and Spider.
Do not waste your Gems. Fully upgrade your Gem Mine when you can. It is a lot of Gems, but the mine will pay for itself in 100 days.
When you can, unlock all Market slots. Ancient shards will appear there here and then, for 200k silver. Not too often, but for a F2P player, that is free Ancient shards.
Your first Arena team may be:
- High Khatun leader - only needs to be *5, speed boost and turn meter boost, a little bit of turn meter manipulation
- Zargala - AoE Decrease DEF and hard hitter
- Athel - AoE nuke, Weaken debuff
- for the last position either Captain Temila - Increase DEF and healing
or Vrask for healing, if you can guarantee Critical hits
or Reliquary Tender for AoE healing over time, full AoE cleansing, and single target revive
or Cardinal for AoE revive and single target healing
As a Rare, Reliquary Tender may be easier to max than the Epics. She is awesome and will help you in many areas of the game.
If you are willing to spend some money, I would recommend the daily Ancient shard for USD 1, and/or the daily Mini Max pack for USD 2.99 or how much it is. You may also want to invest in the month long daily Gems pack, that is one of the best things to get, as it will allow you to max your Gem mine and buy Masteries for your Campaign farmer (800 Gems), saving you a LOT of energy and time farming Minotaur.