First of all, get across the closest defender if they are fairly tight. It buys you time because whatever contact you feel, you can go down and they will get a red card and defenders generally don't want to take that chance. The second defender usually goes around the keeper to cut off a weak shot. He feels that the closest defender can do something, no need to double up on a player. That or they are too far back to do anything.
The keeper is your next priority. You want him to make the decision for you. Keeper is easiest to beat when they are moving. So you want to be able to take the shot early so no long pushes and strides. As soon as he moves, strike. You want to aim for where he is coming from because it's very hard to change direction so quickly. If that doesn't work, make him move. They realise that the closer you are, the easier it will be for you. So try move him by changing angles around. Push it towards your stronger foot as if you are going to strike the nearest post to you. It's bad for a keeper to be beaten there so it's his priority. Usually they move too quickly or too far so you striker across the keeper, far corner. He has to be off balance, even slightly will work. Get it on target, you might have an easy tap or your team mates if it hits the post or keeper pulls off a save.
If making him move doesn't work, get closer to them and fake a kick. If that doesn't work, whack it straight at him and expect a rebound. If that doesn't work, go towards the byline and hope one of your team mates makes a decent run so you square it to them, early.
Good keepers will try to set themselves quickly and rush you into taking a shot when it isn't the right time to. That's why composure is crucial for a striker. It's also very hard to develop.
I'm a striker myself, if you haven't worked it out.