This thread is god aweful and filled with nonsense. For one. what does "tighten up" mean....and please don't say "tone". There is no routine for getting rid of excess fat, if that's what you're looking for....? If you want to make the muscles firmer well just about anything will do when you're starting.
Skull Crushers to me are for the advanced. They are too high risk for me and I don't do them often. Stick with the basics if you're not going to do some complex moves like bench press and dips or pushups. I would recommend you learn the form for your complex lifts first, i.e. Bench press, dumbbell presses, dips. This way you can add more weight later and really get into some body sculpting(not bulking). You can firm up doing enough reps and intensity of any pushing exercise. You shouldn't go heavy with low reps until you've used lighter weights, higher reps as a beginner while you were learning your correct movements. But who wants to know that stuff nowadays...??? We want instant internt like gratification.
On the fliip side, getting rid of fat is a dietary thing. That's another story.
It's 3am where I'm at so I'm going to bed. I may chime in later. Geez.