what should i put in my soil if i grow a plant in soil..??

well today i went to planet k by my house..
and when i went in there to check out what they have to grow..
they have all this stuff for growing like bat guano sea bird guano
and earth worm castings..
what is all that for..
ive grown a plant before but i just put regular soil and it grew pretty big..
but i wanna grow another one but a better one..
so can any body give me advise..??

Really depends on the soil you use.