The biggest mistake people make is to think of a "diet" as something they will have to do only for a few months or a year not as a time to make a permanent change in eating habits. This is true no matter what diet you attempt - low fat, low carb, whatever. If you got fat eating sugar and starches once, then you got thin avoiding sugar and starches, you can bet the ranch that if you go back to eating sugar and starches you WILL regain the weight. I know. I've been there.
No matter which low carb plan you follow, read the book and continually refer to it for information. If you cannot find any books on low carb dieting in your local book stores, Amazon has a complete selection at discount prices.
The general rule is 64 oz (about 2 liters) per day plus 8 oz for every 25 pounds you are overweight. Drinking a lot of water aids in fat metabolism, keeps your kidney's functioning and keeps you properly hydrated. If you are interested in more details as to why drinking plenty of water is important, go to http://members.tripod.com/~Dietman2/water1.html or http://www.blackdirt.net/lowcarb/water.html
Things like Atkins bars may sound like a good idea, but it is best to stay away from them and other pre-packaged "convenience" foods at least through induction or (even better) until maintenance. Some of these products have erroneous carb counts. Atkins bars have glycerin which, while not a carbohydrate, has been know to stall some people. Beware of low-carb sweets made with Malitol which is a sugar alcohol that can be a stopper for some. Read the labels. Experiment if you like. But be careful.
You should not be HUNGRY on a low-carb diet since a low-carb diet stablizes insulin and blood sugar. If you get hungry, EAT something low-carb. Generally, low-carb diets are not calorie restricted. Granted, the fewer calories you ingest the quicker you will lose weight BUT this is not a race - it is a LIFESTYLE CHANGE.
It seems like food choices are so restricted on a low-carb diet that it can get boring quickly. However, it does not have to be that way! Cruise the web to find interesting recipes or buy one of the (few) low-carb cookbooks that are on the market. I didn't realize how NON-boring eating the low-carb way could be until I invested in a cookbook.
In Atkins book he refers to cheese and shellfish as "free" foods implying that they are carb free and can be eaten in unrestricted quantities. Many an unwary Atkins dieter has been derailed by this. Cheese has carbs - it varies by cheese (see my carb counter) and ranges anyware from about 0.1 grams to 1.5 grams per ounce. So does heavy cream - 6.7 grams per cup. Most shellfish also has carbs. Crab is the exception. Raw oysters are at the other extreme containing about 23 grams of carbohydrate per pound. Organ meats (such as liver) also contain some carbohydrate. If you are not careful, you can easily blow past your carb limit with these alleged "free" foods!
One sure thing that will stop weight loss cold is overconsumption of "legal" desserts. I keep my allotment of "legal" desserts to no more than 5 grams of carb per day. Not just because more will start to blow my carb limit but because most of the desserts are very high in calories. Watch the serving size carefully. When Atkins says his cheescake is 12 servings, he means it. Just because the "legal" desserts are low carb does not mean they can be indulged in freely.
This way of eating works best if you plan ahead. If you like to "brown bag" your lunch, prepare a week's worth of lunches on the weekend, put them in the fridge ready to go. Plan quick and easy dinners during the week - especially if you work all day. There are plenty of delicious low carb meals that can be on the table within 30 minutes of beginning preparation. You can also plan to cook a bit extra and use the leftovers as lunch the next day. Once you get the hang of it, eating this way becomes EASY.
Plateaus are frustrating as hell. They happen on all diets and low-carb diets are no exception. There are many things you can try (see http://www.split.com/fat/plateau.htm or http://members.tripod.com/~Dietman2/plateaus.html for more tips) but I have found that one of the more effective plateau busters is to eat something different (i.e. high carb) for a meal or a day then jump right back on the low-carb wagon.
So you went to that party and nibbled on too many high-carb goodies that you've been SO good about avoiding, eh? FORGET ABOUT IT! Nobody is perfect and we ALL have weak moments. Jump right back on the low-carb wagon the next meal. You should NEVER let one indiscretion lead you back to a lifetime of destructive eating. In fact, having an occasional planned "cheat" can be psychologically beneficial as long as you don't do it too often. Sure, your weight loss will be slowed but so what? You are in it for the long haul. And if you've been stuck in a plateau, you just might find that you'll break out of it.
For many people it helps to keep track of how they are doing. It can be as simple as keeping track of your weight on a chart next to your scale, or you can use a program like Weight Commander for more detailed tracking. For some, it also helps to keep a food log - especially during a dreaded plateau.