photo: www.countryliving.com
For me, I have no hard and fast rules. I do know, however, that the right paint colour on exterior doors and trims does a house proud. It entails striking the right balance of colour and restraint...a decision that is not always immediate. Another rule of thumb I go by is to be very careful selecting the garage door colour. If you have a red door, perhaps a red garage door is not the colour direction that will best suit your home. Enlist the opinion of friends with good taste, try out the handy computer programs that enable you to "visualize" the colour choices before you paint, and/or seek out the opinion of a professional...be it a painter or decorator/designer. Personally, I think that if you are simply painting a front door, you can glean plenty of savvy assistance simply by driving around other neighbourhoods and taking note of what you like (and maybe even snapping some photos?), and combing through decor magazines for design inspiration.
Keep in mind, it is only paint; it doesn't have to be permanent. That said, if you are 100% certain you are happy with your colour selection, taking your doors to an auto detailer to professionally spray them will be some of the best money you will ever spend. Not only will you get a durable surface in any sheen you desire, but you won't have to do it yourself!!