Step 1: If you haven't already, install Firefox, Chrome, or Opera.
Step 2: Install Adblock Plus
Step 3: Install Adblock Plus Element Hider
Step 4: Open the Adblock Element Hider
Step 5: Shoot to kill
Disable signatures (no, I don't want to see them again and again):
Disable avatars (nah):
Reputation (even more useless a system than before):
That massive footer (it really is massive):
The less massive header and DDO logo (it really is sort of large):
Posting privileges box:
The RSS icon:
Background image (SPIDERS. SPIDEERRRS):
Anonymizer (makes posts relatively anonymous. Still possible to find names by quoting or disabling adblock):
Smilies (screw smilies):
Report and +rep buttons (you can disable adblock quickly if you want to report someone):
Subject field (damn that text is large):
There are a lot more things you can block, but I won't list them. Just figure it out. You can also block things on other websites: ABP Element Hider is a really useful tool.
NOTE: Since a lot of these filters are wild-cards, they can block things that you didn't intend to block. If that happens, just edit or delete the filter.