How can I improve my workout routine?

This past year my physical fitness and my metabolism, it seems, has completely gone to hell. I’m 5 foot 7 or so and I weigh about 165 lbs. Compared to my college roommates who are all toned and glisteny with seemingly little effort, I’m sortof pudgy, and I can hardly keep up with them during physical activities because my endurance sucks.

A few weeks ago, I started the following morning routine, in addition to cutting fast food, soft drinks, and cutting my portions in half:

1. Stretching
2. 5 minutes of vigorous shadow boxing
3. Jumping jacks (counting to 30 by 1,2,3,4,2,2,3,4, etc)
4. 20 push ups
5. 25 situps
6. Jumping jacks
7. Cool down walk

I’ve already toned up a bit more than I was and I have lost a bit of weight. I don’t feel like I’m making the most of my workout, though.

My goals:

1. Flatten and tone stomach/achieve visible abs. I can feel that they are getting larger and harder, but they are still hidden by a thin layer of fat I can’t seem to get rid of.

2. Bulk up arms.

3. My legs are fine from years of soccer. My endurance sucks, however, and I’d like to improve.

Reading fitness forums on the internet has made my brain feel like it is full of fuck. Everything says something contradictory: don’t take creatine/take creatine, running is absolutely necessary/any kind of cardio works, etc.

With all this in mind, dear reader, what can I do to improve my workout routine to achieve my desired results?