1)Take a look at these http://www.mensfitness.com/fitness/ab_exercises/
2)Maybe your not lifting heavy enough or like you mentioned your diet is poor so if you havent got the sufficient amount of protein in your body your muscles wont grow very well.
3)In my experiance running is the best cardio workout, but give them all a try an see which is best for you.
4)Yes like mentioned above diet is crutial!.
5)When i am running i play music with a fast pace an beat to get into a rhythm. And while weight training i listen to slower paced music again also to help me get into a rhythm.