Microphone preamps.....

[lil_wattage]

Upgrade your mic (s). Upgrade your pre amp. Upgrade your interface. What you want to do is try several mics out, but try to spread your money so you have a selection of things. Also, those liquid channels are cool. I've heard them before, and while some of the replicas may not be very close, some of them are spot on. But if you don't know what you're listening to/for anyway, it doesn't matter.

How do I know what a better interface is. Is it the higher the bit rate is the better?

 

[HERESY]

How do I know what a better interface is

Listen to the interface, read reviews, study the specs.

Is it the higher the bit rate is the better?

Most likely your interface does 24 bit recording. I believe you're talking about sample rates and the higher the better. My take on that is the higher you can go, the more options you have, not the better the sound (in some cases.)