Most Helpful Guy
Infatuation is an emotion and is more selfish than love. You may or may not take action when infatuated, but it is all about your happiness, and feelings as oppose to what the other person feels or wants. If you do something for them just so they will like you, that is about your happiness and therefore is because of infatuation, and is not love.
Love is a commitment to sacrifice, and is always expressed as action. That action can be giving time, money, or effort, but there is always a sacrifice on your part. Much like how a parent must make sacrifices for their children because of love, with no hope of reward in return. You can not love without an action. You can't love someone and then stand by and do nothing when they need your help. Action is how love is always expressed.
It feels good be be infatuated, but it feels good to be loved. Actually being in love often just feels like work in an thankful job, again much like how parents sometimes feel.
Most Helpful Girl
If the only time you enjoy being with them is when you're having sex or messing around in one way or another, you're probably infatuated. Finding many things about them to be irritating if you're just out to eat or something would be more of an infatuation, as you're not wearing those rose-coloured glasses that often come along with love.
Love is more when you're a bit of a giddy mess just being with them. Whether it be just sitting at a beach or park, out to eat, or getting random kisses. Later on when you've been together for a while, if the best evenings are ones spent just cuddling which you're perfectly content with, it's leaning towards love.
Not that those two will mean the same thing to everyone. Many will start with infatuation which will develop into love as they spend more time together and let them see things a bit more clearly as they let the hormones settle down a bit.