Calorie counting and increased exercise are the simplest tools for a beginner.
A great online and FREE calorie counting aid is
Livestrong.com's MyPlate, which used to be called TheDailyPlate. It has an incredibly comprehensive list of nutrition facts for every product I've ever searched for. It's very easy: just put in what you eat, and the site totals the calories for you and lets you know whether you're above or below the calories you need to lose weight.
Something else I wish I'd known the first (or second, or third) time I lost weight: setting goals for yourself is the most important thing you can do. Weight goals are good, and I like to give myself a little reward each time I meet a goal, but fitness goals seem to be held in common by almost EVERYONE who loses weight and keeps it off for life. That's what I'm doing differently this time around--every month, I set myself a new fitness goal, and then I meet them. I also have one huge overall fitness goal that all this is working towards: I'm going to do the Warrior Dash when it comes to NC next year.
I do a lot of positive visualization, too, which is another form of goal-setting. When I'm looking at clothes I like on the Internet, I imagine myself happily wearing them at my goal weight. This is probably one of the best-feeling motivators I have.
Some really great information on goal-setting and goal-setting behaviors is available in Tom Venuto's "Burn the Fat, Feed the Muscle," an eBook I recommend to ANYONE who's interested in weight loss.
Good luck, newbie!