The lowdown on how to get the best fit using Clever Wee Fox nappies, but the same applies generally to all nappies.
Make sure the sides are neatly tucked into the groin just like wearing underwear - you want those leg elastics to gently hug the legs with no gaping or gaps showing when you move the baby's legs
If you have rise snaps done up, you want to push the excess fabric upwards as shown.
A gap at the tummy is okay!
Elastic marks on the legs are okay if they fade or go away with some nappy free time. If they're angry red marks that don't go away, then that's an issue you might need some assistance with. Try making them not so tight and checking that they are washed properly. It could be that brand/style of nappy might possibly not be working for you. (I have found certain brands I used gave my baby more red marks than others).
Thanks Shoshanna Shand for these great pics and tips!