earningguide.com would be good, but this? No... I mean, it's obvious it's online. Poor as a brand, no value as a keyword domain. Just my $0.02.
No friend, online earning is definitely different from earning. Someone suggested me in another thread that "Online SEO" is not a good phrase, I agree because SEO is only online thing, but earning is not.
"online earning guide" - it's an earning guide on the Internet, but not necessarily about earning money online. The online bit is redundant. Something like "earn money online" would be better (from an English point of view) as it's more explicit about the intent. Or even "earning online guide".
Well I take it as Online Earning Guide (a guide of online earning) We are not talking about what can be better. domains (especially and specifically .COMs) are NOT YOUR CHOICE anymore, they are highly subjected to availability. Make Money Online can be the best, but I don't have a million dollar to grab it.
No offence was intended, mate. I know .com isn't so readily available, but if you're marketing to a native speaking audience, then a domain correct in terms of grammar, word order and spelling is going to be more appealing (and trustworthy). Unless you want word-of-mouth traffic, the TLD doesn't really matter (with the way most browsers work these days, losing type-in traffic is a bit less of an issue and also SEO is the same regardless - Google has stated they treat all extensions the same, obvious difference would be local search) for this type of site (it's more about information and not an online shop, for example). However, if your market isn't native speakers, then such a word order won't matter as much.