Make sure you don't use a country specific TLD like .co.uk or .eu. They tell Google you're targetting a local market. Top level TLDs like .com and .net will tell Google your audience is international in scope. See Google's blog post on working with multiregional websites for more.
If you have multi-lingual content you should follow Google's new multi-lingual guidelines. Basically, you use subdomains for the different translations:
To explain how it works, let’s look at some example URLs:
http://www.example.com/ - contains the general homepage of a website, in Spanish
http://es-es.example.com/ - is the version for users in Spain, in Spanish
http://es-mx.example.com/ - is the version for users in Mexico, in Spanish
http://en.example.com/ - is the generic English language version
On all of these pages, we could use the following markup to specify language and optionally the region:
<link rel="alternate" hreflang="es" href="http://www.example.com/" />
<link rel="alternate" hreflang="es-ES" href="http://es-es.example.com/" />
<link rel="alternate" hreflang="es-MX" href="http://es-mx.example.com/" />
<link rel="alternate" hreflang="en" href="http://en.example.com/" />
If you specify a regional subtag, we’ll assume that you want to target that region.
Keep in mind that all of these annotations are to be used on a per-URL basis. You should take care to use the specific URL, not the homepage, for both of these link elements.
Otherwise the SEO is essentialy the same (quality content, semantic markup, quality links, etc.)