Control that sweet tooth. Remember that sweet things generally mean more calories. It is natural that we have cravings for sweet things especially chocolates and other confectionary. Go easy on theses things and each time you consume something sweet understand that it is going to add on somewhere.
Fix times to have meals and stick to it. Try to have food at fixed times of the day. You can stretch these times by half an hour, but anything more than that is going to affect your eating pattern, the result will either be a loss of appetite or that famished feeling which will make you stuff yourself with more than what is required the next time you eat.