It's good you came here and posted. Welcome to the forums. I'm fairly new too, but I've been doing a lot of reading.

Read all of the stickies up at the top of this page. They'll address a lot of your points, although there's a few I'll address myself - not as a replacement, since I'm not as well-versed as the guys who wrote that stuff, but as an add-on:

"It seems like the saying "Lower reps, higher weights" is a bunch of crap because I haven't noticed anything."

There was a nice layout that 0311 - a frequent poster here, and pretty much the man - had where he talked about different rep ranges, and what each one did for you. The bread and butter for size/mass (which are directly related) is the 4-8 rep range, so fairly low. There are definitely reasons why you aren't seeing a big change, and one of them is this:

"I only focus on my upper body stuff, and never bother with the lower body."

You HAVE TO work your lower body to stimulate growth. I lifted for a full year and some-odd months doing just upper body, thinking I'd get big, and I gained almost nothing. I got stronger because I had my newbie gains, but then I started doing my homework and doing squats and deadlifts, and now I'm 40 pounds heavier than I was when I started the lower body/back workouts, and my bench is up like 70 pounds. Start doing squats/deadlifts as part of your routine and you will see a big difference. Besides, having a huge upper body and no lower body would look weird as shit.

"I work out my chest, biceps, triceps, forearms and shoulders almost everyday until Saturday for about 30 minutes in the gym."

Two problems with this: I don't know what kind of workload you're using, but for a beginner, you want a lot of recovery time. 24 hours is not enough if you're lifting heavy. What's more, if you're doing chest workouts like a bench press, you're hitting tris and shoulders too. You run the risk of burning out in the gym - a huge risk, really - by working out every day, doing the same thing, and doing a huge-ass workload.

And, of course: EAT! What are your stats (ht/wt)? You should be getting tons and tons of calories if you want to bulk. But as with all of these topics there are going to be guys who can help you better than I can - starting with those stickies!

Good luck.

-Connor