Use a good quality soil.
When building up the soil, you need to ensure it is compacted from the bottom up. Use your fist to firmly press in the soil round the edges to prevent settlement, which will cause root ball exposure.
Try to maintain the same soil level as the nursery. Do not plant too deep or too shallow.
Water all around the pot. Don’t just water in the middle and use a good fertiliser on a regular basis.
Finish off the pot with a layer of pea gravel. Not only will this help retain moisture, it will also act as a decorative feature.