Rules for swamp:

1) Never land your boat in the swamp until you're in silver or better. Do whatever it takes to land in Black Forest (or Meadows if you're close enough to the middle of the map) and work your way in.
2) Carry poison resist meads and keep the buff up when you're in the swamp. Don't wait until you see blobs or leeches.
3) Use your hoe to create paths so you don't get stuck swimming or have leeches biting your ankles.
4) Don't run in the swamp until you're in silver or better. Same for going out in the swamp at night.
5) (Optional) Use your pick to lower the ground around surtling spawns into the water

Like in my current game my Bonemass spawn was all the way on the edge of the map on an island I couldn't safely land on. I landed in some nearby black forest and built a cart-capable bridge into the swamp (since I still needed a lot of iron and there's always tons of crypts around Bonemass).

https://steamcommunity.com/sharedfiles/filedetails/?id=2819651739

The spawns were relentless, I think due to a combination of distance from the center and proximity to plains and swamps. I was wearing bronze armor at the time and it was rough going, so I built a fortified dock in the black forest with a smelter and a level 2 forge so I could craft iron armor in something resembling peace. I got the copper for the forge from a nearby copper node, the iron for a stonecutter from a crypt, and used a grinding wheel to upgrade my forge. I think I built it there but you can take grinding wheels through portals, which is one of those obscure-but-occasionally-super-useful things to know.

https://steamcommunity.com/sharedfiles/filedetails/?id=2819652920
https://steamcommunity.com/sharedfiles/filedetails/?id=2819651791