I am running a farmer and would like to know how I can tell if i have won a block or not?
You will want to check your reward address on the Subspace/Substrate explorer.
If you have not yet setup your account on the polkadot.js extension refer to this post
Another way is to check the log of your farmer, if log says “successfully signed a block” then you won it.
Almost. You might need to check node’s logs for re-orgs as well, it is possible that farmer signed the block, but block was pruned as part of non-canonical chain, see Сoin disappeared from wallet balance - #2 by Diana_Subspace