A few things to check for:
Psychologically, what do you think before playing those jumps? If you think, "Oh no, here come those difficult jumps" then it will be ten times more difficult. Believing you will make it is a pig part of actually making it. Make sure your mindset is "I can play jumps like a baws".
Regardless of what you think in your mind (though it will hinder you more when you are worried), another thing to check for is tension in the shoulder area. In fact, tension anywhere in the arm makes it much harder to aim. Check that you are not "holding on" to any muscles around the shoulders, and that the hand and lower arm are allowed to travel along the keyboard with complete freedom.
Third thing, make sure each jump is one, smooth continuous motion.
Don't do this: place hand over d - play d - lift hand - place hand over b flat octave - play b flat octave - lift hand - move hand to D flat - play d flat etc etc.
Do this: play d, and let the contact with the keybed send an instant impulse to move the hand in a smooth arch down to the B flat octave and sink down to the keybed, all in one motion. Don't try to stop and aim, let it move smoothly and trust in your aim (in other words, practise in a comfortable pace!). For practise, you can exaggerate the arc and lift the hand to the height of your shoulder, making sure you arm is free and supple through the entire motion.