Hi Anthony, here's an even more simple method for the "build extended" type strategy.

One thing that can be good is to try and see if your shape is an overall cutout of a larger more regular shaped piece.

If I understand correctly, you do have something like that here, and this is the larger piece:



So take this edge:



And fillet it, so you get the source of the larged curved portion here:




That's the "underlying form" right there.

Now take 2 curves drawn in the Top view plane like this:



And run Boolean Difference on the main piece and select the curves as the cutting objects. That will slice it up like this:



And now you can delete the pieces you don't want, leaving you with:




So that's even more of the kind of "build larger and then trim out pieces" kind of strategy.

It can just generally be a good way to go if your object has the overall impression that it has some underlying form that has been cut up, try to actually model it in that same way...

This tends to require you to kind of imagine what the missing pieces look like, sometimes it can be hard to get used to doing that but it can be a good technique.

- Michael