Use patches with a feathered edge like rema.
Clean, sand, apply THIN smear of cement over area greater than patch, centred on the hole.
My LBS advised 2 very thin coats.

wait
Apply patch to exclude air. I bend the patch, contact with the centre and let it roll out. With smaller patches, you can roll them on from one side. Apply thumb radially from centre to edge, quite hard.
Remove paper/cellophane by cracking the material in the centre and peeling from centre-outwards.
Any force from the centre inwards will act to raise the edge.