Welcome to minimins Louisetegan!
First off well done for taking the first step and starting LT today. Yes I dont like the strawb much euther but if possible you can ask your chemist to swap them for another flavour you like?
As for water they say say at least 2 litres, but some say the more you drink the more you shrink!! I think anywhere between 2 and 4.5L is best, thats just for the water.
I ahve about 4lt a day myself. As for advice well pop on here and feel free to ask any questions you want to, were all here to help and have been in your shoes at some point of another.
I would say take a peek through the old threads, for inspiration and to get a more general feel for the programme.
The first week you will be heading into ketosis usually around day 4-7 and until then you may have a headache or feel tired - BUT this does go and once your in ketosis you will feel brill, you shouldnt be feeling hungry.
Just keep glugging the water and you will be fine, it usually cures a headache and hunger pangs.
As for the shakes you can have them hot too, if you have a hand blender or blender (but ovb not just boiled), you can add a coffee to the vanilla and chocolate, the vanilla one ends up tasting like a yummy latte, you can add ice so their cold like a smoothie - really nice.
Erm you can have sweetners too to jazz things up a bit but they must be saccahrin. Anyway thats all I can think of for now, im sure others will be along with more advice.