Definately eat or drink before you start the battle! We're never late but getting out the door IS stressful. Mine all have a list on theire bedroom walls - I've written it into the form of a funny poem to remind them of what they need to do.
This is my downfall, too! I found making myself wake a lot earlier to have a quiet cuppa and listen to the radio, and then have my shower before I faced encouraging them along to get ready really made a difference, too.
I decided no matter what they got up to, yelling would only make them and myself feel far worse, and committed to trying to stop...(not a nice way to start their day, don't want my children to remember their mum not coping with poor behaviour and yelling every morning)
I started taking an apple and water or a traveller mug of coffee with me in the car to sip on every time I felt like raising my voice when they were annoying each other/getting silly in the car (difficult to take shrieking/silly antics in a confined space). Having something to pop in my mouth stops me from getting cranky and basically behaving badly when I'm at my worst time of the day- when they are behaving badly as all children do at some stage. Only thing is the traveller mug has spilt a few times on my work clothes!
I am too. I shout when they run riot at silly o'clock so I can't have a cup of tea in peace, I shout when they think it's funny to have a wee but I need to use the look (a lot) as I have IBS, I shout when they dance around naked for 20 mins when they should be doing anything but.
I know everyone moans about teenagers sleeping in but I'm at the end of my tether these days <and breathe>.
If they would stay in their rooms quietly until 7am I would be a lot happier.
Start at the time when you need to leave to comfortably get to work on time. Work back from there, noting how long things take - teeth 5 minutes, shoes/ coats / bags 5 minutes etc. Do you start off when you get up or earlier?
also, set timers around - you have 10 minutes to get dressed etc. put timer on and then ignore and do your own thing. If they're not ready, they go as they are.