Okay so my writing work tends to go like this: I get an awesome idea for a new book and I plan it out and begin writing and I'll be really into until i think of a new idea, not necessarily a better one, but because it's new I'm more into it so i end up abandoning my old novel and starting a new one and the whole cycle just goes round again no matter how hard I try. Anyone got any tips cause I would be so grateful!
Perhaps you can try to develop a more disciplined approach by writing some short stories? Set out to accomplish something smaller in scale and see how that works. Take note of what you did to keep going to the end. Learn what works for you.
One other tip (a bit gimmicky, I know, but what they heck) is to write out your plot, characters, chapter outline etc etc and then write each chapter as if it were a complete short story in and of itself. Every day, something new to write, that in the end comes together as a whole.
In the end it's something we all need to master, the discipline to finish, and the only way to master it is to do it. To persevere and to battle the urge to be distracted. Once you have completed a novel the first time, you will take with you the skills and experience needed for the next one, and the next one, and the next one ....... hopefully ;-)
I agree with victoria you really do need to be one with your idea before commencing on or you will continue on going round and round. So sit down in a quiet place and have a really good think to yourself before writing anything else down. Good Luck.
If you want to laugh about it, I suggest this.
http://www.wikiwrimo.org/wiki/Plot_bunny
I did once hear someone say that if you can be distracted from a storyline easily then it might not be strong enough to hold a reader's attention either. You need to find something you're really passionate about so nothing can distract you and perhaps look forward to the way your work might affect future readers so you are motivated to finish.