Grip Kit:
keep as many options with grip kit as possible..... grip kits can save the day many many times..... take as many tripods and light stands as you can..... you may not always find assistants to hold lights...... sometimes, lack of proper grip kit can even get expensive equipment damaged!!
and if you place lights on the ground, they'll create multiple problems with unnatural shadows..... its also a pain to hold diffusers...... tripods and light stands are the solution..... take as many as you can, even if its a pain to carry them..... and take as many clamps, clips, rope, tape etc. to improvise....
Diffusers:
take all types of diffusers, especially the bigger ones, as they can help you take a full-body portrait..... less than ideal models would always force the photographer to look for full-body portraits...... close portraits would be more appropriate for models with better facial structure and skin tone.... smaller diffusers would then be very useful..... umbrellas can be the most cost-effective way to diffuse light if light fall-off on the background isn't an issue.....
Reflectors:
bigger reflectors are needed if they are going to be used for full-body portraits.... small reflectors are OK for close portraits; so, they're always useful to have.... its always quite tricky to make proper use of reflectors, as they cast a huge amount of light...... mastering the art of reflector photography can be a target for the future strobist meets....
Warm Gel Filters:
these are exceptionally useful and can create late afternoon sunlight any time.... they can make a rather bland picture pop.....
Number of Strobes:
take as many as you can...... this is especially for group portraits.... sometimes, while trying to overpower the sun, more than one flashes may be needed..... bigger, and more powerful strobes may help even more in this regard......
Strobe Distance:
have to be very careful about this, as strobes can cause flare on the lens if they're too close to the subjects while taking group portraits.....
Models:
we definitely need more models for smoother shooting...... photographers can be models, but it would restrict the learning of the photographers in some way..... dedicated models can go a long way in this regard.....
well, these are some of the lessons that have come to mind.... others can share more....
