My MIA makes gemstone jewelry, I upscale used furniture/small wood items, my wife does high-end paper crafts.
My MIA makes the most money/stuff because she doesn't work, my wife and I's are more hobbies as time allows. My suggestion is to go to the local craft fairs, and see what it available in your area, what is selling, and how much. We changed our strategy a lot on what we sell after doing several shows.
Mainly, the less expensive, the easier it is to sell. One of the things I make that sells real well is I do hall coat/hat racks that are about 3 feet long, with a top shelf, then I used dollar store picture frames and/or mirrors, and embed them, and then add coat hat hooks. I do the whole farmhouse look (Joanna Gaines distressed style). I look for really cheap wood furniture, real wood, on craigslist that I cut up. Oak TV entertainment centers can be picked up real cheap.

Especially those that don't fit the new widescreens.

I also get a lot of my wood from recycling pallets/skids - but stick to the hardwoods, not the hedge which is most common. In the fall I do christmas trees with pallets that I sell for $50, and only spend about $5 on paint.
The craft shows will give you ideas. Women like to buy holiday themed crap. My wife and I are making V-Day and St. Patrick's day front door hangers (like a wreath) right now, selling for $15 to $20.