How To Restring A (Soprano) Ukulele

Old joke:
Q: When should you change your ukulele's strings?
A: When you won't need to play it for 10 days!

It's been said that all jokes have a basis in fact. This one is no exception. New strings can stretch for up to 10 days. You'll find yourself retuning almost every time you pick up the instrument (and sometimes while you're still holding the instrument) until the strings settle in. This is NOT due to a fault in the strings or the instrument. It's the way new strings behave.

For soprano ukuleles, I have found that tugging on the strings before I tighten them helps them settle in a LOT faster, BUT

1. Don't overdo. The ideal is to have about two winds on the peg once the strings have settled in and
2. Do NOT tug on the 3rd string (the thickest one). Make it as snug as you can without raising its pitch before tightening.

Finally, if you play in GCEA, tune the uke to ADF#B. Both the uke and the strings should be designed to handle the increased tension.  The strings will slip but keep at it, checking every so often. You'll retune. The strings will keep slipping.  That's okay.  The idea is to get them to the point where they don't slip below GCEA. Make a final ADF#B tuning before going to bed. In the morning, the strings will have slipped a bit but will go into GCEA just fine. (As a further demonstration of the perversity of nylon/flurocarbon/nylgut strings, when the strings are dropped into GCEA, they will remember that they were tuned higher.  They will go out of tune sharp(!) for a short time until they settle in for real.

That part about going to bed is another way of saying let the uke sit for a bit.  I've used this technique to restring a uke in the morning and take it to a jam in the late afternoon.  Eventually, you should be able to, too, but see (1) above. Don't press too hard the first few times you try this.  With practice, you'll figure out the right amount of tugging needed.

Something like this technique may work for concert and tenor ukes, but I have no real experience with them except for the occasional concert uke. So, I'm afraid you're on your own here.