Getting started. For the first build, everything can be overwhelming. There's wood selection, milling, assembly, finishing, and setup. All with their own little quirks along the way.
I would suggest starting with a simple kit, to get your feet wet assembling pre-made parts. Then, a more hands on kit that allows you to bend, make the fret board, etc. If you stick with it, a lot of skills will become second nature and you can then start experimenting with thicknesses, bracings, and bling.
Also, don't be discouraged if two ukes built from the same plan come out sounding very different. There are a ton of variables that luthiers need to take into account. From the raw wood, to subtle thickness differences, bracing patterns/thickness, sound hole position and geometry, and setup. A few minor changes can add up to a big difference in sound. The more you build, the better you'll understand the mechanics of what influences what.
For me, to this day, the hardest part is getting started. I like to have all of my pieces prepped and ready to go, but I rarely get the chance to do so. I force myself to start projects, so I don't fall more behind on my build schedule. Unfortunately, I end up generating parts on the fly and it feels like I'm going so slow. I try not to rush, but when the pressure's on, I have to. More often than not, I end up ruining something and having to make it again. You'd think I would have learned by now.
