Why do you stamp your foot to the music? Its because of the beat/rhythm – the nerve of the song. This you produce with strumming.
First of all, a stroke or strum is defined as a sweeping movement where a finger nail, nails, thumb, or a plectrum brushes past several strings for paying a chord. When you are not using a plectrum you normally use your nail down and tip of your finger up.
The dominant hand is mostly used for this action, but some left handed people also do this with their right hand for avoiding altering the string on the Ukulele.
For strumming use your wrist and not the whole arm. This is important! The best place to hit the strings is for the most Ukuleles around the place where the body of your instrument meets the neck, but you have to thy it out for it can be some differences between them.
Furthermore, you need to learn Strumming for playing good Ukulele songs!
Plucking is the opposite of strumming. Then you just sets one string in movement, and plucking several strings simultaneously requires a technique called finger style or fingerpick.
Fingerpicking can also be on one string at the time as plucking. For instance the fingerpicking as you can learn in this video for Blues Pattern.
It is very important to have a constant beat while strumming. For helping you out you can therefore use a metronome. You can use a normal metronome, or you can use one downloaded to your phone as an app. Normally you hold the beat by counting (1, 2, 3, 4 for 4/4, and 1, 2, 3 for 3/4) until you get it into your hand and head.
For learning to strum you need to learn some strumming patterns. It is several of them, and they also can be changed during the song. If you don´t know which to use for your song, then you have to try out strumming patterns to fit it.
Stumming patterns can be showed as text (D U or d u) for down and up, or arrows (down and up). The – indicates a missed stum, and an X can be a sign for a chunk down (muted stum). Se our post about Chunking here. (d) or (u) can indicate a muted strum in either direction with you fretting fingers resting on the strings to mute them.
For making a percussive click you also can use a dead strum. This is made with your fretting hand. You simply stop the stings for ringing by laying your fingers across all of the strings.
For starting with some simple strumming patterns:
Down, Down, Down, Down by counting one, two, tree, four (DDDD)
Down Up, Down Up, Down Up, Down Up while counting one and, two and, tree and, four and. (DUDUDUDU)
You can also try this two the opposite way: Up, up, up, up or up down, up down, up down, up down
Down, down up, down, down, down up (D-DUD-DU)
Down up, down, down up, down (DUD-DUD-)
Down, down up, up, down up (D-DU-UDU) (called The Island)
For making it more interesting you can in addition try out Swing Time. The down strum is longer (about twice as long) than the up strum.
D-DU-UD- (one and, two and, tree and, four and). This is a popular pattern.
Half-bar Patterns where the chords changes regularly
Two Bar Pattern if the chords changes more slowly. The song will be better if you change between this two.
D-DU-UDU and -UDU-UD-
For ¾ you can try out this ones:
If you want to learn more clearly strumming you can watch the video below. Using your thumb to get more power and in addition how to position your index finger for down- and up-strums, for getting more clarity and control.
How to strum really fast:
Watch the especially relevant video below to learn:
Here is another demonstration with the use of four fingeres up and down.
Finally, now its just to practise. Good luck!