Firstly research your plant to ascertain whether it would be better potted or grown on a mount. With the exception of a few most are better grown in pots particularly hybrids.
When potted it is most essential to use a coarse open mix (no fines) of a good hard bark and charcoal and addition of gravel is beneficial. I feel clay - terracotta pots (squat well drained) are a must in hotter areas.
Mounts can take many forms old weathered hard wood palings etc. (not treated timber) cedar, bottle brush, gutter guard containing bark and gravel and live trees eg. Callistemon even citrus but NOT heavily leafed, the likes of Avocado, Macadamia, Mango etc.
Housing is critical dappled shade such as live Bottle Brush. Grevillea etc. is ideal but not always practical. The alternative is shade cloth approx. 80 % or heavier with very good air movement and plants down lower in the house.
If growing species Sarcanthinae those best grown on mounts are Sarcochilus falcatus, Sarco. hillii, Sarco. olivaceus, Sarco. dilatatus, Plectorrhiza tridentata, Plrhz. brevilabris, Rhinerrhiza divitiflora, Peristeranthus hillii and generally the smaller species but strangely when crossed onto the larger types of Sarcochilus they grow quite happily in pots (as above).
Watering is fairly critical in hotter weather. Never in the heat of the day! Don't allow plants to remain dry for any length of time. A good soaking 2 or 3 times a week is generally adequate in summer and less often in winter but always thoroughly wet the mix each time.
General rule of thumb is that the larger the pot and plant the coarser the mix. Do not overpot - they don't like it. You can build your specimen plant by gradually increasing pot size never just pot on. Remove old mix and dead roots before repotting. Repotting can be done at any time except during a heat-wave! Don't be put off - if your plant looks unhappy it could be that the mix has broken down and they go backwards at a rate of knots when this happens!
Overall Sarcanthinae growing is very rewarding and by keeping to a few hard and fast rules success is assured!
Bev & Frank Simpson Simpsons Orchids