Hello everyone and congratulations on your efforts to complete the c25k program. I am one of the coaches who implements this program and after working with hundreds of graduates of a modified version of the program I'd like to pass along some tips that I've found help with issues that frequently come up with runners looking to conquer their first 5k.
Motivation: There will be times you don't want to keep running or even get started. This is normal. It will help you to write down your goals somewhere and keep them posted where you will see them often to "brainwash" yourself into remembering this. The benefits of doing this will be a much healthier body and MAJOR sense of accomplishment. It is NOT silly to write down goals on paper.
Injuries: Aches and pains are almost inevitable when venturing into uncharted waters as a runner. Look forward to this. Most running injuries are preventable by being smart. What REALLY helps is having at least two pairs of shoes to alternate, varying your paces each day (don't just go out and plod along every day), running on a variety of surfaces, icing anything that hurt and getting in some nutrition right after a run.
Food/diet: Don't overthink it. Just eat as much healthy food as possible. Some splurges are ok but remember that goal sheet you put out!
Good luck and please post any questions/issues you are struggling with and I'll do what I can to help.
Also, some other USATF and RRCA coaches and I came together to create some GREAT (I know I am a bit biased) training plans and have started posting them at HowToRun5k.com and they come with a TON of goodies that tackle the issues above and much more.
Runner, Teacher and USATF Coach blogging at TeachtoRun.com.
Also working with RRCA and USATF coaches on creating "The Ultimate 5k Plan" at HowToRun5k.com