A wee bit of a warning though.
When you raise up a doodad (or lower it) and then try to move it it will "fall" to the ground again.
If you make say a building out of bricks stacked on on top of the other and select the whole thing and do copy and paste, all of the doodads will "fall" to the ground.
Also you need to consider making things like roofs to where you ignore model clicks. its under Editor - Ignore Model clicks. This way you can access the doodads under it. If you need to move any object that you have ignored, just go back to the editor and reset Ignore to false.
It is always best to raise the ground where a planned building will be with the hill tools (not the cliff) then flatten the ground out with the platue tool. This way your doodads will be flat, and in the case of using layers of say bricks you can select and copy/paste a full layer, setting them were you want and using CTRL + Page up or Page down to raise and lower them. Once you have placed all your doodads select all of them making up the structure - raise the structure a couple of page ups, then go back and "fix" the terrain, lowering it whatever with the valley tool, hill tools, platue tool. Then select all of those doodads again and lower the whole structure as one.
Aligning doodad can be rather simple if you give them a small pathing like Barrel. This way when you plop doodads they will align with the grid. No pathing means that you have to use the number pad (7,8,9 |4, 6 |1,2,3) a lot to align them.
One you have them aligned you can remove the pathing.
For stacked structures I suggest making a copy off the doodad, set its name to TEMPORARY XXX (xxx = name of the doodad) Use that to do each layer. after you get the layer set you can select the whole structure and use Advanced Replace doodads and replace the TEMP version of your doodad with the permanent version.
This will allow you to use the Ctrl+Shift+~ to select all doodads of a type so you can easily select all of the doodads you are currently working on without selecting ones you have already placed.
Hope something out of that helps.
