Wanting to paint my front door

I have a palm sander, and l was planning to give a quick sand around the frames - door has 4 panes of glass, wipe down to remove dust.

Any other prep needed?

3 beers. It's a 3 beer job. Oh and a bit of masking before the beers, cos you'll be wobbly after.

Don't use water based paint. Use an enamel paint, it is slower to dry but the finish is so much better. I learned that the hard way.

I usually check the frame where it meets the glass on the horizontals and give that an extra clean out, especially in the corners.

How long does the enamel paint take to dry on a warm day? I want to paint my front door too, but worried that it will be still tacky by night time

Most of the day really, make sure it is a warm wind free day, esp for the final coat, and anything you can feel with your hands will show up, make you do really good preparation and feathering.

Painting a door in enamel isn't an easy task. But it is worth it.

Depending on the type of paint that's already on the door, and if you are changing the colour, I would recommend an undercoat first. Most water based undercoats are fine under enamel.

A few basic tips.
After the undercoat, a light sand with 180 grit. Be careful on the corners.
Get a really good quality brush for enamel.
Thin the enamel with up to about 10% turps to help it flow easier. That will also help you paint faster.
A cooler day is actually better. Around 15deg and not in direct sun.
Paint around all the glass first, just slightly onto the front face. Then the rest, one section at a time. Paint an even coat as fast as you can and don't keep going over and over it - smooth it off quickly and move on - the brush marks should flow out themselves while it dries.
You will need two coats of enamel. A light sand in between.
I could go on and on.

A couple of other things. Get yourself some good quality washi masking tape. You can use it to mask the glass (if you want) - it's usually worth spending the time masking the glass to save time painting the 3 coats. Mask about 1mm away from the putty, so the paint goes onto the glass (clean any old paint off the glass first!).
The other thing you use the washi tape for is to mask around the door frame edge where the new paint will touch when the door is closed. Where the new paint touches the top of the washi tape, it won't stick. Leave the tape on for at least few days after the last coat.