I have two accounts on Blockchain.info. I'd like step by step instructions preferably to how I can keep my current + future coins 100% safe from hacks, forgetting password, authorities shutting down the wallet etc. Seems like authorities can shut down any site they like (recent example btc-e). If I back up my private keys or something like that, maybe then I'll never lose the coins even if I forget Blockchain.info password or if it gets hacked or shut down etc. Right? I'm not sure how it's all done. Please advise.
Your question is complicated since you have to do many things just to make your coins safe. In terms of hacking as long as your bitcoins are placed on a hosted web wallet there is a tendency that it is a possible victim of hacking even giant site are being attacked and so if you store your bitcoins in a hosted web wallet is has still the tendency of being hacked if the site is hacked.
If you want your bitcoin to be safe from hacking store it in your flaskdrive or a hardwallet. But of course if you are not careful it is also some dangers in it.
And do my advise to you my friend is to place your bitcoins on different kind of wallets on different sites. This may not offer 100% guarantee but it would lesser the risk. Just always keep with you the private keys and password or otherwise you cannot access it.