Drying time:
Oil paintings take around 6 months to dry fully, but are touch dry (and able to be displayed) after around 2 weeks. Good airflow helps oxidize the paint faster, thus speeding up the drying time.

Storage:
While the painting dries, you should hang it to prevent it gathering excess dust. Keep it in a well ventilated room with a relatively stable temperature, and avoid damp environments like bathrooms. Avoid putting it in direct sunlight, and obviously, avoid spillages or places where it might get knocked down.

Fluorescent paint and Inks: 
IMPORTANT! If your painting contains fluorescent UV reactive paint, be aware that this paint will fade with time. Due to the nature of fluorescent dies in paint (namely their organic nature) no fluorescent paint exists today that does not eventually fade. If you would like it to stay vibrant and UV reactive for as long as possible (years or even decades) avoid putting it in direct sunlight, and avoid exposing it to excessive UV light. If you want to experience the UV reactivity in the least destructive way, use a UV torch, and do so in short bursts. Sadly, nothing lasts forever.

Varnish:
If you chose to have your painting delivered before it was fully dry, after the 6 month period, it will need a varnish. to do this, simply take a make up brush and gently brush any dust or hair that may have gathered on the painting. then, take a Dammar Varnish spray can, and spray it over the painting in a thin coat, holding it about 30cm/12in from the painting and allow to dry for up to 24h. Do not varnish it before the 6 months have passed, as this will result in both the varnish and the paint cracking. 

My recommended Dammar Varnish Spray is the one by Winsor & Newton, which can be found on amazon, Ebay or any local art shop. 

Best Practices:
After the painting has dried, I would recommend to still avoid direct sunlight, as it may make your painting start to yellow over time. I would still say to avoid spilling anything on it, or sticking anything to it. Keep away from Flames and Children.