If you can't get .com then don't worry. Other extensions .net, .org are equally valuable. It all depends on how you wanna use the site. Focus on creating quality and meaningful content; in a long run the extension does not really matter the most. Visitors like quality sites, they don't care if it is .com, .net, or .org. Well, that's my opinion; even though I know .com is the most preferred.
Also, if you can stay away from buying domain names that are too long., it's better. It's hard to get type-in traffic with those names.