when you find a spawn location either destroy it or form a stone wall around it using the hoe. once you get the wall around it about 4 - 5 high, jump inside and start using the pickaxe to make the edge vertical so they cant walk up.

it can take some time, but it works well. there are areas where enemies will still spawn even without the spawn location there - yet this will greatly reduce their numbers.

for a base look for a place that is already a slight hill and then start to cut the edges vertical and then you can build your base on the top without them bothering you too much. make sure you give yourself at least 4m from the edges since log trolls can still reach with their swing. the rock ones can also reach more, but once you get the stonecutter then you are golden. make getting the stone cutter your priority and building will be so much better.