MyFitnessPal Virgin

-track every bite
-invest in a food scale and weigh your food
-keep your weight loss goals reasonable. .5-1 lb of loss a week for healthy, sustainable loss.
-don't undereat all the time. Try to meet your calorie goal as close as you can.
-if you exercise, eat at least half of your calories back that you track. MFP already calculates a deficit without your exercise.
-weight loss is not always linear. Sometimes your weight can go up and down. As long as it stays in a downward trend and you feel the difference in your clothes/how you look and feel, you're on the right track. The scale is not always your friend!
-you do not have to exercise for weight loss. However, exercise has other health benefits, especially some sort of resistance training to help reduce the amount of muscle you lose in the weight loss process.
-take progress pictures and your measurements. You may not always see a difference until you compare side by side images!
-read the stickies. There's lots of helpful advice in there.

Good luck! Welcome to MFP.