balance your chakra's. i don't want to say focus on your third eye, it's a bad idea, but having your third eye open will help you with your goal. try finding a crystal with properties to aid in clairvoyance, and meditate with it over your third eye. before meditate, or doing anything prophetic, try having a psychic tea.
you could also take a deck of cards and try to predict which one it is. start with 'red card' 'black card', then move on to suit, face card or number card, and finally the whole card like 'seven of diamonds'. another thing you could try is make 3 predictions about your day. sit and concentrate on your day, don't go with 'go to school' since you do it on a regular basis, but something like 'pop quiz in english' or 'fire drill'. [if you want to be really ambitious you could try and predict a time]