OK, at this point you can actually play the thing! Cool, eh? It takes quite a while for ukulele strings to quit stretching - don't worry, it's the strings, not the instrument bending. Just keep playing it, re-tuning, and playing it some more.
During this break-in process, you may as well adjust the action at the nut. "Action" refers to the clearance between the strings and the frets. You should be OK at the bridge end due to all that checking with a thread you did earlier, but the nut end is probably going to need adjustment.
What you're after is to make it so that strings are not stretched out of tune when pressed down on the frets. When it's brand-spankin' new like now, shoot for about 1/32" between each string and the first fret. Err on the high side, and keep in mind that the nut will wear over time, lowering the strings a bit. Press down each string and look at how far it travels before it hits the first fret. If too high (too much travel), pull the string off to the side and carefully file the slot in the nut a bit deeper. Go slow, check your progress often, and make SURE that you are ALWAYS cutting down at a slight angle towards the tuners.
Properly done, you'll notice that everything sounds more in tune as you play, plus it will be easier to play since the strings are not all high & stuff.
You're done - congratulations! Put away all the power tools, pop open another beer, and start playing :-)
Back to the start
If you find any of this helpful I'd certainly appreciate a "tip" :-)