Here are a few tips. They represent what I have found to be mostly true in my experience and hopefully, will give you an idea of what to expect and how to help me create the best portrait.
What to wear:
There are two simple rules I like to follow: 1). Wear what you are comfortable in and what makes you most happy. 2). Wear clothing and colors which complement each other rather than clash. Subjects who stick out too much will have attention drawn to them i.e. some who wears a very bight color while everyone else is wearing white or subdued colors.
Come with appropriate footwear for the location we're using whether we use footwear or not.
Colors can be just about anything as long as they don't clash. I'm not a real fan of black tops/shirts at outdoor locations but, it's really up to you. Sometimes it works and as long as you like it.
I like to have attention directed to the faces in my portraits even if it's an environmental portrait (full body shots showing the scenery) so we don't want too much skin though we, don't want you all covered up. For the ladies, that means dress cut below the knees and for those who are conscious of their arms looking big (pretty much all of you :), something that covers the shoulder with a short sleeve works to minimize the perception of the arm. For men, that means, no hairy legs, worse if your shave them :) Kids are OK with just about anything.
With that said, we have clients who come wearing a variety of styles and I always seem to make it work, so wear something that's nice and what you like, after all, it's your photo.
Yes! Daytime appropriate make-up works best, whatever works for you. If you don't like too or use very little make-up, no problem though we do recommend that you have some foundation or at the very least, corn-silk or any other similar pounder which will eliminate the shin caused by persperation and oil. Many times I'm using flash and this will tend to cause oily skin to shine more than we like.
About young children:
If you have young children (under 5 and especially under 3) it's very important that the children are well rested, fed, content, and happy. It does no good to bring them at the time they should be napping or waking up from their nap. Sleeping in the car and waking up at a strange place isn't good either. Consequently, you'll want to schedule your portrait session at the time that works best for them, not for you FYI: If we are scheduling a session for the best light, try to prepare you children for the time a couple of days before the session date.
I suggest you not make a big deal saying, "we're going to do photos, so you have to xxxxx", unless, your child is old enough to understand this and has had good experiences with this sort of thing in the past. Just say we're going to the beach or something nice.
Do not give your very young children food to nibble on or items that they like to put in their mouth to placate them just prior to the portrait session unless, you want those items in the photo.
You know your children, so we'll leave it up to you. But, if your child is at a particularly cranky or unpredictable part of their life, I suggest you hold off on your portrait. It's better than re-scheduling a portrait session, which is an additional cost.
Finally, don't stress out too much about your kids, they pick up on that. Try not to give them too many commands, etc.. Let them do what they want until we're ready for them.
Portrait sessions are not time based but, plan for an approx. session time of 20 and sometimes to 40 minutes. Usually, I do 2-4 pose set-ups and generate between 30 to 100 images for selection. Proof images are presented on the website for selection.
You can bring cameras to photograph anything that I am not photographing. I do not allow people to stand near me while I am working with subjects. I may allow people to take a few shots from the side as long as it does not interfere with the session. I have a few reasons for this. 1). When anyone is standing behind, near, or even to the side, one sunject always ends up looking at them and thereby ruining the shots), and this happens quite frequently. 2). It's very hard to keep the subjects attention focused when people are acting as distractions (it's hard enough even with no distractions to keep subjects focused).
I set session times to give us the best opportunity for the best lighting given the time of year and the location. With that said, I cannot predict the weather, if I could, I'd be retired :) Consequently, we may adjust the session time for the best light and conditions. Usually it's not more than 15-20 minutes from the originally scheduled time. If possible, try to schedule enough time in the day for this possibility. If not, no big deal, we'll just do what we can.
If you are planning a dinner or other event after the portrait session because you're "all dressed up anyway", please make sure you give yourself enough time. It really doesn't make for good photos when you are thinking about rushing off to a dinner. Also, you really don't want to schedule your session on the same day as a major event you have to be at. It's will be stressful for you.