Im becoming a lacto-vegetarian, i'd like to know what foods i should watch out for in ingredients?!

So my family is pretty supportive I guess you can say, I'm the only one in my house who vegeterian, I guess I wouldn't call myself that yet since I've only gone a few days not eating meat etc, though my mom doesn't like me becoming vegetarian I still want too, I love animals and don't believe they should be killed for human purposes they have feelings as well,so I'm a lacto-vegetarian though I'm trying to eat less diary products as possible, no yougurt, milk and cheese little as possible, sour cream too, I know I should watch out for gelatin, but what else do I have to keep a look out for?, and cheese I eat Monterey Jack Cheese, do they use animals for the make of that? Plz help! Thanks.