Amber you don't really need a trainer or gym membership, you can do a lot of the exercise and fitness routines yourself, you just need to research a bit first, how to do them safely.
Kiramon, I'm basically tracking my calories as accurately as possible, I signed up to www.livestrong.com (it's free) and I use their feature called myplate which allows you to essentially keep a diary of what you eat, I've set a weight loss of 2lbs per week in their calculator and it comes up with a daily calorie limit for me and I stick within that, whenever you add food to your daily amount it re-calculates how many calories you have left. I'm 6'1" and 216lbs at the moment, a 2lb per week loss is approx 1600 cals per day for me.
Other than that I do weight lifting a few times a week to try and keep my muscle up while I lose weight. I started doing this mainly to combat muscle loss, I've read that when you come off your diet you'll naturally put a lot of the lost weight back on and a lot of that is muscle, so really I started it as a preventative measure. Actually after a few months of doing it, I'm enjoying it, my arms and shoulders look good
The only exercise I really get is walking to and from work every day, about 15 minutes each way and about 30 minutes of walking at lunch when I walk in to town and pick up some food, I don't exercise at all right now.
Just stick at a reasonable calorie limit, don't overdo it, trying to lose too fast can mess with your metabolism, slow and steady is the key.