What is the simplest way to up your reputation points so that one can use all features offered by this site?
Short version: Ask good questions and give good answers.
I'm not saying you would, just putting it here to deter anybody considering it.
There are several apparent weaknesses in the system where you might think you could gain extra points but most of this is automatically logged. Puppet accounts, for example, are very easy for us to spot (even with different IPs) and when we do, we can undo all the effort in a few clicks.
In short: it's not worth it and you'll just look silly.
Edit bad spelling and grammar in questions and answers! For every successful and thorough edit you do, you'll receive +2 rep (up to a certain maximum)
Also, if you do this: Don't cheat! e.g. adding irrelevant tags which just takes you 2 seconds to add, but takes a reviewer 10 seconds to review is frowned upon!
By being awesome. Look at the people with high rep, and read through their question and answer history. Emulate their awesomeness.