What's the site? It's okay if you want to keep it secret. Majority of them do not require going to such extremes as making a VM. But some do! Most you can really do there is optimize the VM to take the lowest amt of sys resources so you can increase efficiency. google phraseslike "optimize virtual box windows" and you'll find tons of little tricks and methods.
As for emails, most sites ban the major disposable email providers like sharklasers 10minmail, yopmail. A gold nugget secret is go on google translate and turn "disposable email" into another language like swedish, then search it on google.se. play with different languages, you'll find many disposable email domains that have not been blacklisted. another option is you can buy 1000x [gmail/hotmail/yahoo/etc] email accounts fairly cheap on vendors like buyaccs.com
next big thing is proxies. some sites check if all accounts you're making are coming from the same IP. some sites don't. once you figure out if this is indeed a factor, it's easy to scrape proxies online or buy in shared/private packages. if you have a vpn thats fine but i've noticed these ip's are getting frequently put on blacklists too. they may have tons of ip's in their pool and you'll need to have a way to quickly rotate the connection for a fresh ip.
if this site you're trying to spam has crazy security thats cockblocking you, you may want to play around on
https://panopticlick.eff.org/ and make your footprint non-unique.
i'm sure you're already aware of spoofing user agents/browser/system time/window resolution, clearing LSO cookies, etc. if you search bhw you can find some threads on this kind of info.
depends on the site you're hitting. may work for site A but be blacklisted on sites B, C, D. i would agree most are shitlisted.
