first of all i kindly ask people down the lane not to flood the topic with posts like "only retards play mp3" or "the warm feel of vinys is so much better"

i was wondering: how should one take as much as the mp3 sound can give. i mean EQ tweaking, gain, burning to CDR, playing on CDJs etc.

anyone have some advice? tips, tricks? how to make mp3 sound decent...

im a noob to encoding...

im interested in playing mp3 that where already encoded before me. you know what i mean. i would certainly play the original source if i had one
so, how should one maximize the mp3 sound

By leaving it exactly as it is.

(Applying EQ and filters to MP3's tends to only bring out the flaws more.).

Only thing I can really recommend, is running the MP3's through MP3Gain. This way you can get them all to approximately the same volume, also you can make sure that the MP3's won't "clip" when played or decoded.
(Clipping is when the sound is too loud and the peaks of the waves get cut off, which makes the music sound distorted.)

The only thing you could change is the gain, preferably using something like MP3gain, so that it's all normalized. However, even the gain of tracks is easily previewed and changed in a DJ mixing setting. EQ'ing should be done in the live mixing/DJ-ing setting by previewing the track you're playing next, and determining whether or not any of the EQ bands need tweaking.