The midwives at my antenatal classes said you need to drink between 2 & 3 litres of fluid a day. Which I struggle with, as like you I never drank a lot of fluid before hand.
The best things I have found to get more fluid are:
Having juice with breakfast
Straight after breakfast, having a hot chocolate (the ones you just add water) with metamucil in it
Having a bowl of fruit on the table to snack on
Having a cup of soup as a snack (either by itself or with something)
Having a bottle of water or weak cordial on the bench & have some every time you walk past
Icey-poles, tinned fruit or jelly
Always having a drink with a meal or a snack
Keeping a bottle of water by the bed for in the middle of the night

HTH