Taking list and changing them is what I mostly do.
I've got "experience" in deckbuilding as in : I'm deckbuilding since 3 years now, but I'm nowhere good enough ( yet
) . we're also a bit early in GRN for me to give definite advice on deckbuilding.
my best advices are: keep brewing, insipre yourself from what the others do, read articles about why/how people brew their deck and approach metagames. Learning from others + trials and errors.