For a starter, you don't want to choose a mark that's fairly similar to what's already out there.
If you are making a new internet search engine, don't name it "Goggle" or "Yahou!" Your common sense and conscience will tell you why. Similarly, don't name your search engine "Stanford Internet Search."
A clearance search can be cheaply done by a Google search. Search the names you have in mind (or what you're using already). Not only that, search goods or services that compete (or would compete) with yours. You definitely want to know what their names are.
Avoid any confusion at all cost. You probably shouldn't call any of your good/service "Coca-Cola." Nor can you call your soft drink product "Soda."
Next, your mark should stand out.
You can't name your concierge service "Luxury Concierge Service." Well, technically you can, it's a free country. However, the law won't protect your trademark because other companies should be free to say they offer a Luxury Concierge Service.
You need to be creative on this. "Kodak," I think, is a superb trademark. It's short but distinct, original but easy to pronounce. Don't worry if you're not good at making up words. A common word like "Apple" can be a good trademark for a computer electronics company.
In today's world, an internet domain name is as important as a trademark.
A domain name registration does not necessarily mean that the name is taken as a trademark by others. However, you probably want to avoid someone else owning YOUR_TRADEMARK.com.
If the name in your mind is still available for a new registration, get it immediately. The domain registration costs less than $12 a year. (It's as easy as setting up an email account.) If it's owned by others, consider buying it from the current owner or finding a better name.
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