Living in the UK, most of the best clothing in our wardrobes is probably winter stuff so why not encourage people to get out and about with their favourite coats, hats and scarves and have fun shooting some outdoor winter portraits.
During the Winter months, strobe lighting can help bring out details and highlights that might not be captured without it but this doesn't mean it should be given prevalence over natural or tungsten lighting. By not overusing one particular light source, you can produce a variety of images, giving your subject more choice at the end of the shoot.
Sometimes you'll find the flash, colour balance and ambient light will conflict but in the right settings, this can give fashion type portraits a great look. Try playing around with the white balance setting on your camera to give surrounding daylight a cool blue tone. For portraits with a warmer feel, set your white balance to cloudy.
Don't forget to pack a good reflector as these can be really useful for redirecting winter sun and take your longer lens along which can be used at wider apertures to create sparkling highlights in the background of your shots – Bokeh to those who like the technical words. A spare battery or two are useful and if you want to shoot some indoor shots after walking around outside for a while do remember that moving from outside to inside on cold, damp days could mist up your lens and camera eyepiece up and some acclimatising time will be needed.
Rural or urban locations can both work with Christmas lights adding further interest to town and city shoots at this time of year. It's a good idea to have a route in mind so have a look for potential shoot locations before the shoot day actually arrives and it's also worth factoring in a cafe or bar stop along the way where you can make a pitstop. This will give you the chance to warm up, apply fresh make-up etc. If you're heading for woodland, bright clothing can work well as it'll contrast against the trees which are starting to take on their winter appearance.
Think of ideas and adjectives that'll help you portray a theme to your subject and do remember to help them relax so they don't feel so self-conscious when you're taking their photograph.