Please to be Evaluating my Workout Routine

[samsonite2100]

I recently, about a month ago, started working out for the first time in my life. Due to the fact that I hate gyms and am busy, I've tried to put together a small, manageable routine I can do at home.

Every other day, I do a set of pushups to failure, 50 crunches, 15 reps with the ab wheel, another set of pushups to failure, and 50 more crunches.

On my off days, I just do some form of cardio, jumping rope or whatever. And I walk at least a couple of miles every day.

Also, I do about ten minutes of stretching every day, as well.

My goals with this routine are overall health, strength and flexibility, but I would also like some increased muscle definition, as well. I should say, I'm already in relatively good shape, i.e. I'm not a fatty and have a low BMI, and have already noticed some results in the definition department.

What else can I be doing or could I be doing better? What am I doing wrong? Please be gentle as I'm a total exercise noob, and I've just kind of cobbled this system together from reading stuff on this board and a couple of others. Thanks in advance...