Hello and welcome. As the others have said, drink plenty of water, and you can split your packs to make more drinks if you want, just add half the amount of powder to half the amount of water (or more water if you want).
Try adding coffee to the chocolate shake mix, it gives it a "mocha" type taste, either hot or cold. Personally I hated the flapjacks and the soup was quite watery, but its a personal taste and worth trying all of the flavours to see which ones you like.
You might also find that your tastes change during the course of the diet, and you might want to try others that you originally didn't like.
Keep posting on here and ask any questions you want, there is always someone who will come along with answers and advice. There is a great support system in place on Minis x x x