Counting carbs can be done with radical protein diets such as Atkins, but the weight loss won't last. Remember that all vegetables are carbs, too. Different people require different diets. Avoiding grains, for example -- whole grains are actually fine, it's the simple carbs that are the problem. Permanent weight maintenance is more complicated than a fad diet. See a holistic nutritionist and figure out what suits you best -- might be a vegetarian diet high in grains. Have you seen many fat macrobiotics? They mostly eat whole grains. So everything depends, it just isn't that simple.
A low carb diet consists of mainly vegetables and unprocessed meats ( no hotdogs or already made things containing meat.)
Things to avoid would be grains, fruits, corn, potatoes, etc. This is really hard to do because it leaves out a lot of the sugary things in your diet, that overall, people seem to crave.
However, carbs aren't all bad. A lot of the energy we get for the day comes from carbs, which makes them pretty important. Too many carbs can be a problem.
There is no general number of carbs you should have a day. You should take your age, weight, and total life style into consideration. Which means you will have to do some digging.
Hope this helps a bit. Good luck!