Guitars are like flavors of ice cream, when you have good ice cream you can enjoy each of the flavors that they have to offer. If it's bad ice cream, it doesn't matter the flavor it sucks.
Go for a guitar made out of solid wood all around, this lets the guitar breath and sound the best it can. Depends on the style of music you are playing. Classical is great for learning because the strings are easier on your fingers, acoustics with steel strings are best for projection and that overall great acoustic sounds.
The clamp is a capo, it allows the key of the guitar to be changed.
Go to a music store, play on a 200 guitar, a 1000 guitar and a 2500 guitar and notice what the differences are. It's one of those things that you'll know when you know if you are good enough to realize why you would need a better guitar.
Tabs online are a great way to get out of ruts, lots of options with sites showing you how to play. You can't get over the fact that you have to play and practice to get better.
