Yeah, what thomasfl said
PrinzII- OK, now I have a clearer take on your weight lifting regimen. Glad to hear you're rethinking it, more
Short (?) lecture on muscle fibers: Muscle groups are comprised of a mixture of "fast-twitch" and "slow-twitch" muscle fibers. The f-t ones are the ones that really grow and are where most of your power comes from. The s-t ones are the ones that can have great endurance; they don't really grow bigger, they just learn to work LONGER. Think of how some long-distance runners look TOO "stringy"/scrawny (like they need a good hearty meal) and how male gymnasts and sprinters (who go pretty all-out for short periods of time) have lean but MUSCULAR bods. That's a so-so example, but generally you oughta concentrate on the f-t fibers, which should be worked for the 20-50 seconds (OK, MAYBE up to 90 seconds max). The big exceptions are calves- go for up to 2 minutes on them.
Bench press example: 2 seconds to push it up, maybe a second (or less) at the top, 3-4 seconds to lower it back to starting point= 5-7 seconds per rep x 8 reps=40-56 seconds per set.
Unless you have some specific goal in mind (like being able to do 50 pushups or 25 chins or something similar), you really do want to keep the reps sorta low.
Start off with 20 rep sets with a light weight while you learn good form. Proper form is the most important thing!! Slow is better than fast, and AVOID momentum/body english. (Feel free to ask about any exercises you'd like form-advice on.) Then raise the weight to where you can (only) do what I outlined above- >1 minute sets with strict form.
rightlane- Good searching! BUT.. once I got to 2fit.com, I couldn't find the video
The "trick with "skulls" (besides NOT bonking your head, see 94AccordSedanEX's suggestion if you're more sensible than I am, and you SHOULD be! I ALWAYS spot my wife's workouts) is to keep the weight heavy and the reps low. That will recruit the long head whereas it will "loaf" under lighter loads, allowing the other 2 heads of the tris to do the work (and they get work with most every OTHER tri exercise). Don't let your elbows flare out, even if it means using a lighter weight. Go for a REAL stretch at the bottom, like letting the bar touch the bridge of your nose for a count of "one". DON'T "bounce" at the bottom or you can hurt your elbows!! Grip the bar pretty TIGHTLY, it'll take strain off your elbows even more and stabilize your wrists. Oh, and you should pick up the bar with a THUMBLESS grip (thumbs BESIDE your index fingers, NOT curled around the bar like holding a hammer, this is AKA "monkey grip"). Then when you lie on your back to do the exercise, your palms will be facing UP towards the ceiling. Again, be careful, especially when you release the bar after your last rep. BTW, DECLINE benches give a better effective range of motion than flat ones because gravity pulls straight down (and the bar isn't over your head quite as much).