Villagers are what make you a god and what makes villagers is having housing, food, water and defence.
But that doesn't help when the second wave is too much.

-Start in the middle you won't know which direction the enemy is coming from, but the moment you do you can start work on cutting off half the map regardless.
-Don't get trapped trying to start in a valley running out of space means relying on stupid villagers to actually do their job -> you know better by now than to allow that.
-Instead of throwing the enemy anywhere find a closed section of map to 'fire pit' them; or (& mind not to overuse it) 'mana pit' them.
-Your best bet are mana towers for defence though they require garbage burners and have mana well battery backup to power the towers. It's main draw is that it's wireless and when don't you have garbage ?; also on the plus side more mana = less reliance on peasants.
-Spread the love and by the love i mean pick up monsters and move them between towers so they don't get overwhelmed/completely drained. Worst case scenario pit monsters and use the fire spell to slowly roast them (called fire pitting.
-Protect what you own, but don't stop monster pathing. walls around towers can keep them from being overwhelmed while keeping the horde moving on your mana sourced towers spreads out the love.
Don't wall if you don't need to wall every 3mm is anouther job task to distract your workers for making actual defences or nomad attracting houses.
-Don't bother with any offensive spell but fireball on full offence; none of the others seem to do anything to monsters. Even fireball though is completely weak compared to mana towers.
-resurrect your dead and make sure you keep enough to do so; having enough people to build is having enough people to expand and once your down to 7 builders forget about things getting done by nighttime meaning every loss becomes a permanent setback.
-Golems are shite, the spell summoner one can't even deal with 2-3 enemies from the second wave and frankly that otherwise regenerating mana bar is better used for pitting.
-However with a quick change of spells from their drop menu under icons you can get 'courier golems' and they seem to function as slightly less stupid villagers because they are not 'builders'. don't use anymore than 1/3rd your mana bar reserved.
-Villager's are 'builders first'` gatherers second and seems to get thrown off task whenever you manually move resources. So take note off what they are currently fetching for a fetch for some other building. I mean they are bad enough wasting time dancing to the 4 corners of the structure just to dump their load, don't make em think for gods sake your doing it for them because they WILL slack off.
-If it's still not fun try to remember the dev seems pretty open to patching; play peaceful and throw him/her tips how to improve the game.

=Hope that helps