Sometimes if you put different shaped bowls or even some wide drinking
glasses around the house in various places, it will encourage cats to drink
more.  They instinctually want to test the new sources of water to make sure
they are good.  Some cats like running water, so you might want to try one
of those pet fountains.  I have one, and my cats love it.  Only problem I
have with it is it can be a PITA to clean.
Also try ice cubes in the water dish.
If your cat is eating mostly canned though, she is probably getting most of
the water she needs from that.

-Kelly

Cats have a relatively weak thirst drive, to begin with, because they
evolved to obtain almost all of their water needs directly from their food
(live prey).

Cats fed canned food that contains ~78% moisture need to drink very little
water.  A 5.5 oz. can contains about 4-5 oz. of water.  The cat's daily
water requirement is about 1 ml/kcal or about an ounce/lb.  So: although
your cat may seem like she's not getting enough water, she probably is.

If you want to increase her water intake, you can give her the water from a
can of tuna packed in water (not oil).  You can even add a little more water
to the tuna water to increase her water intake a little more- although she
probably doesn't need it.

You can get a rough idea of a cat's hydration status by pinching the skin
behind her neck.  A well-hydrated cat's skin should snap right back, a
dehydrated cat's skin won't.

Phil.

My cat loves to drink from whatever I'm drinking from.  She tries to stick
her little nose in everything.  I also noticed she's not drinking much
water.  Some days, her bowl doesn't appear to have been touched.  So, I put
a little coffee mug of water in the living room, right by the kitchen and
near other water.  She drank out of that but she can't get very much from it
because her little face can't go in the mug very far.  So I upgraded her by
putting one of those large "cups" that are really bowl size in the mug's
place.  It's the kind that looks like a really big mug.  So she drinks out
of that one now and seems to like it better.  She goes back and forth and
whenever I refill either of her water dishes she tests them both.  I'd say
just try something new to get her interested.  I did that weeks ago and she
still likes it.

Beth

Try getting a small pump driven fountain near one of the cat's haunts.
I've yet to meet a cat that didn't like lapping at the flowing water.
Be warned that if you have a large open resevoir and a pukie cat (Or it's
hairball season), you might occasionally have a mess to clean up.

My monster seems to enjoy water in the quart size plastic fast food cups
as well.

I may help to put the water not too close to the dry fooed (it heped with my
cats).
Also cats like natural water (rainwater). Try collecting that for a change.

I have had most success in putting the water in other rooms than the room
the food is in. The bathroom is a big hit and by the couch, and by the big
window.

Try the Drinkwell Water Fountain.

Adam