I find with the water thing 2L in a jug looks like a lot, so I just use a bigger than average glass (my one at work is over 350ml) so you get way more in six glasses than you think and it's not so hard IYKWIM? That way even if your are pushing it, if you have one before and after a meal you get your 6 glasses in without trying.
I try to have one though everytime I go to the loo (I have had kidney failure though and drink about 3L a day)