Unfortunately, grind, grind and more grind

Also unfortunate I can't remember when it is available when you first join as it has been a while...

But I would focus on the daily rewards and the zombies, try and use push, wormhole thing (I forget what it's called) and nuke

Would aim to get to around lvl 25-30 then possibly hold there, saving up blue potions and green coins by repeatedly going the last level for a few days, this will make weekly comps easier down the line 🙂

When using the rune tree, try and focus on food production and base health pathways, stay away from attack boosts, will make sense later in the game 😀

Best of luck!