I remember when I first got a GuitarPort and thought I'd just plug-in and, voila, instant massive Marshall tone!
Boy, was I in for a surprise!
The POD is never going to sound like a real amp, so you need to change your expectations regarding what kind of tones you can and can't get out of them.
Working w/ the POD will teach you the art of compromise. No, you can't get a "million dollar" tone, but you can get a 250K tone.
For starters, learn what amps sound good and which ones don't. The Marshall clones, for the most part, sound pretty crappy, the Silver clone being the exception, IMO.
The Engl clone is very good though, in that it mates well w/ other amps in dual tone mode.
The Diezel clones I'm not so sure about. Might be that I haven't found the right amp/cab/mic combo for them yet.
The Cali Diamond Plate is a good choice for a starting point. It's "thick" sounding amp that's good for chords, but single notes seem to sound a little thin w/ it though.
The Orange clone was an amp that, until recently, I never ever used (probably because I'm an idiot, lol). It is, however, proving to be an excellent
choice for a dual tone. I've found putting a ts in front of it, and cranking the drive and gain, gets a surprisingly good tone out of it.
The Line 6 Big Bottom is another amp that I like to use as a "shaper". Meaning it's a good amp to pair w/ another to bring out that amps best qualities. It is, as its name implies, fairly bassy, so pairing it w/ a relatively "thin" sounding amp makes sense.
Cabs seem to be the POD's biggest weakness. Which is probably why so many people use impulses w/ theirs. That said, I find that I use the V30s, L6 4X12, and the Mesa 4X12 almost exclusively.
Mics. There's only 4 to choose from, so it's a relatively easy process of finding which mics work w/ what amp/cab combo the best. Everyone seems to use either the 57 on/off axis, so that should tell you something. Personally, I like to use the condenser mic w/ the L6 4X12 on some tones. Especially ones that need a little more definition.
EQing. A subject I know almost nothing about. What I do know, is that mids need to be controlled and, at the same time, maximized in order for your tone not to become either too shrill or too muddy. There's some very good responses up to posts made on this subject here, so I'd make extra sure to check them out.
