Firstly, as a girl, I would recommend a Shewee (the guys found this very funny) and if you have your own tent a wide mouthed bottle so you don't have to brave the freezing cold and rocky outside to get to the loo tent in the middle of the night. Don't worry, all embarrassment goes out the window very quickly on this trip!
You do get a bowl of hot water to wash in morning and evening, but wet wipes are really handy, first thing in the morning it's normally a bit too cold to brave 'washy washy' outside your tent!!
Make sure you have enough warm clothes for summit night, it was minus 20 which is really really cold. despite 2 hats, a hood and two lots of good quality gloves I was freezing. Lots of us had fingers going numb.
Whilst hydration packs were useful throughout, on summit night the tubes froze, despite insulation and insulating tubes. This was a real pain, especially when you're struggling. Bottles are therefore better. You need to have enough bottles for 2-3 litres a day.
Most of us got on well with Malerone. I also took Diamox as felt I needed it. Do take plenty of painkillers - you will get headaches. Also, energy drinks and gels are good for summit night cos it's quite hard to eat anything when your appetite has gone. The guides will check your health every day. Do tell them, they all have first aid training and if they think you are not well enough to continue they will send you down.
Go with an open mind, and don't be scared to go alone, half of our group of 12 did. Be prepared for a really tough challenge, but for much fun and laughter along the way. Standing at the top just blows your mind.
If you get a chance to do the 1 day safari on the last day do it - it was a great way to end the trip, see a bit more of Tanzania and loads of animal close up.
Lastly, enjoy cold Kilimanjaro beers around the 'spitting' wood burner in the hotel...heaven :-)