I entered IFS/UPT with 0 hours and was fortunate enough to drop a Hog. How to get from A to B? From my experience it boils down to knowing yourself, commitment and timing.
1. Knowing yourself: I know I"m a quick learner so I wasn't too concerned about getting hours beforehand. That being said, if you know you are a bit slower to get things down then when the firehose hits (and it will) I can see where previous experience will provide you with a solid foundation to help you stay afloat.
2. Commitment: For the majority of both phase 2 and 3 I came home after a 12 hour day, ate dinner and hit the books/chairflew until I went to bed. Every single night. If you want it that bad you will put up with seemingly never ending groundhog days and consequently do well.
3. Timing: This you can't really control but you can work your ass off and hopefully put yourself in a position to be there when the aircraft you want drops.
There are many small steps to take to make it to the end, take it one day at a time and good luck!