To answer this, we need to look at root notes as they are the base that chords are built upon. If we take the notes of a scale and number them from 1 to 8, you will find movements between notes 1, 4 and 5 consistently sound better and stronger than between any other number. Let's take a look at a scale (for learning purposes we will use the C Major Scale):
It might be a good idea to get your guitar out at this point and just have a play around with the notes in the above scale so you can hear what I mean about strong movement between numbers 1, 4 and 5. Also, play around with some of the other numbers to see what some weaker movements sound like.
So, now that we have established the above fact, let's use it in some chord progressions.
A turnaround progression is a sequence of chords that can be continually repeated due to strong sounding chord movement between the ending and starting chords. In the following turnaround progression we use the F chord (F being 4 in the C major scale) to get back to the starting chord C (C being 1 in the C major scale):
Try playing the above chord progression using a strum of your own. If you don't know the chords, they are shown at the bottom of this page - you will hear that the progression sounds good and repeats itself through a strong chord movement.
Here are some more turnaround progressions for you to practice: