Domain selection. The domain name should be short, easy to remember, and should not allow alternative versions of spelling depending on pronounciation. This way, it will be easier for the users to remember the address of your site and to recommend it to other people.
You can tell Yandex robot which site name is the main one, using the Host directive (for example, www.site.com and site.com). Make sure that the content of www.site.com and site.com is completely identical.
Hosting selection. When selecting hosting for your site, take into consideration the access speed and time to failure. Try to find hosting with the best connection speed and the least downtime due to technical problems.