Cats are natural climbers. Height offers certain advantages like
security and spotting of prey. Your kitchen counter may provide a
vantage point appealing to your cat's instincts. However, more often
than not, the reason most cats jump onto kitchen counters is that
they develop (over time) positive associations with this food preparation
area. Their guardian spends time there, makes their dinner there,
gives them treats there and likely even feeds them on the floor near
a counter. From the cat's perspective, it becomes as good a place
as any to wait for and in their minds, supervise the preparation of
their own dinner. Often they have come to expect offered samplings
of their guardian's dinners during preparation. They may as well have
found that diligent counter surfing can result in the discovery of
tasty tidbits inadvertently left behind. Overall, it can eventually
become an irresistible environment and discouraging the average cat
from jumping onto the kitchen counter can take a little creativity
and planning.
You are going to have to find ways to make your countertop unappealing. There is a variety of mechanical devices now available to hiss, vibrate, and/or spray whenever the device detects the cat on or even in the proximity of the counter. There are plastic mats sold with surfaces that discourage counter-top cats. A counter left covered with aluminum foil or strips of two-way tape, also provide a surface that cats typically do not like the feel of.
You will likely find the process moves along faster if you can associate the cat's dinner and treats with another area, like the laundry room or perhaps one of those combination scratching post/cat trees.
Animal Behaviourist John Wade (http://www.johnwade.ca/)