As for the BYOC kits, I've done 4 now and have another 4 or 5 in the works.
The best advice I can give is to read through the instructions until you understand them before opening up the kit.
It all seems pretty straight forward but there can be some tricky steps that only experience will expose. The instructions are written by someone with that experience.
If there is anything that doesn't quite make sense, check out their forum. They have lots of tutorials on the techniques and skills required for a successful build.
It's not rocket surgery, but following the instructions and doing a little research can save you some frustration.
I've only ever had to troubleshoot one build and the amount of reading I did before trying anything gave me two things to check and a clear set of tests to verify the problem. I was done in half an hour.
If you're not good with a soldering iron, practice.
Always tin the wires.
Get a good soldering iron. A 15W pencil will do but just be careful about leaving the heat on for too long.
Don't press the iron into the circuit board. It feels like it helps transfer the heat faster (and it probably does a little bit) but it's more or less like pushing the button on the TV remote a little harder when the battery is dying. It doesn't really do any good and you're probably going to break something.
A good 80/20 solder will flow quicker and better, letting you get the heat off of the board and the component sooner.
Take your time. If you get frustrated, walk away and come back to it later.
Have fun.
I have the OD II to build soon. I haven't started thinking about graphics yet. So, check back in the winter. I might have come up with something by then.
I've got the Armstrong Twin and the Divided Octave as well as a couple others that I can't recall at the moment.