How can I tune a Ukulele so it's one semi-tone higher? Can this be used for 2/3 semi-tones as well?
I've tried using a capo but it makes it a lot harder to play.
Ok, So now that I've heard the song you mentioned he is definitely using the D-tuning (A-D-F#-B) that is mentioned below and, I think, with re-entrant tuning. So onward with the breakdown of Ukulele tunings. It would be ideal to use a ukulele pitch pipe to tune but using a standard guitar tuner should work.
I'll start with the standard C tuning. Holding the Ukulele like you're going to play it; from the top string the tuning is:
G - C - E - A
So essentially if you want a semi-tone up you would use (obviously pitch pipe won't work):
G# - C# - F - A#
For D-tuning which is quite popular and gives a more "sweeter" higher pitched tone than the standard C you would use (try us the pitch pipe's A note for the top string and tune the rest using it as a reference like you would tune a guitar - http://www.howtotuneaguitar.org/tuning/how-to-tune/ (Guitar tuning)):
A - D - F# - B:
Now there are two ways of tuning the top string (G-string); "linear" and "re-entrant". Linear is more like a guitar where the top string is lower in pitch than the string below it (C-string). In re-entrant, however the pitch of the G-string is higher than the string below it (So this could be what they mean by an octave up, but its only and octave for the G-string)
Note: When using re-entrant tuning the G-string is usually a different string type than linear so that it can be tuned up higher than the 2nd string using the linear type G-string would probably just snap it.
There are other tunings like slack key (G-C-E-G) and one for the baritone uke (D-G-B-E) but I think essentially the most common are the first two.