Tropico 4

1) Once your population hits 300, change the speed of time to pause (Right trigger + left on the d-pad). This will prevent more shacks from being constructed while you follow the instructions below.
2) Next go into your menu (Y) and choose Infrastructure --> Demolish.
3) Make your rounds around your island looking for as many shacks as you can find visually and demolish them. This only takes a minute or so. Make sure to look all around buildings and in spaces in between, as well as by the sea shore, especially if you have Fisherman's Warf's or Tourist Docks.
4) Once you have completed a fairly thorough visual search, go into your almanac (right trigger + Y). Use RB to go to "Lists" (far right).
5) Now use the d-pad to scroll down to "Residents-Housing", and again using d-pad go over to the right pane to find all the people living in shacks. You may need to hit "next" a few times.
6) There should only be a few people left in shacks (I had 6). Go to the people listed under Shack, press A (to display their information), and using d-pad scroll down until you get to their house. Press A, and it will take you directly to their house on the map. Repeat the previous steps to demolish.

Repeat steps 4 - 6 until you flush the last of them out.

7) Set the flow of time to anything other than pause (right trigger + d-pad right), and after a few seconds the achievement should pop.

Hope this helps someone.

Once your population reaches 300 try to get everyone into a home and out of a shack. The shacks can be hard to spot sometimes but if you want to know not only how many ppl but who they are, go into your almanac and go to lists and look under housing. It will break down what each person is living in. Then click on the person or persons who are living in shacks so you can zoom in on them and find out where they are living so you can put a house down nearby. When I was down to just three ppl I paused the game and manually destroyed the shacks my demolshing them and when I unpaused the achievement unlocked.

So after making a big economy and having over 400+ people and shaks I got bored of seeing them and bought the USSR trade mission it gives u apartments for half price permanently. I then quick built at least 30 of them near shaks and watched them all move over to there new homes. I also gave the apartments climate control to boost the odds of them moving and to make use of my nuclear power plant. But I had a tiny problem some people wouldn't move right away.

A little trick here that I had to resort to, to get the achievement some people don't move from their shaks right away even if you have alot of housing so simply demolish their homes.

Yeah its harsh but now they can live in something that isn't a shed.

Remember to check everywhere that you have a building with workers since they will live next to their place of work as much as they can. I had to built an apartment for one shak on a mountain just to get the achievement.

Good luck this is a pretty easy achievement when you have a decent economy and alot of space.