DaCowThough,
okay, so there is a lot of things that you could change in your ramp deck. The "problem" is ... for (almost) every card you have in that deck there are better alternatives. Now I get the idea of making a deck with the cards you own and try to make it work... (I ended up with a ramp deck in the same way and it does pretty decent).
About the ramp:
While it is a good idea (especially in green) to go with "get mana faster than other ppl and finish with big guys" this deck does not contain much synergy.
It feels a bit like you just put in random green cards that were laying around and hoping for the best.... For example if you want to use
centaur battlemaster you should maybe consider having the whole deck revolt around him. His ability is pretty decent. For 5 mana he comes into play pretty fast and he'll snowball way too fast.
So i would suggest the following:
Take out:
axebane stag, bond bettle (won't trigger the centaur),
cowl prowler,
druid's familiar,
cowl Prowler,
spined wurm and so on...
(take out basically everything that does not help you getting the centaur out faster or make him stronger
Put it:
blossoming defense,
rancor,
giant growth.... stuff like that!
I know this would kinda ruin your deck idea but if you really wanna go ramp/big you need to think this all over.
Put in more mana generators (and better ones!) use
elvish mystic instead of
golden hind for example. And try to get some "bigger" threats... your creatures that are in it right now are just too basic.
They don't have effects nor do they really do damage - any good tribal will have stronger creatures, any rush down deck will shit you on turn 4 and any control deck... well how will you
remove enchantments or artifacts that kill your game?
I could go on about this all day but I doubt that makes any sense.
Maybe you can DM me or get in touch if you want me to explain in detail
Regards
Milmaster