By knowing you computer specs and following the guides on the gentoo site. Wikipedia, google and Duckduckgo are good for this kind of info.

Try compiling it in something like virtualbox first. If you can, when installing your primary install try chrooting or something so you can have web access.

Another option might be finding something like sabayon linux followed by compiling everything over again from source to get the same performance.

If you have no idea what I'm talking about stick to current operating system. It's not for beginners and ween linuxfags like to push gentoo because it is higher-tier in terms of complexity with a good return performance wise. I think SourceMage and it's sisters (Lunar linux and Sorcerer) are better personally at doing gentoo et al.'s job (which it predates) but the lack of support and the ease of fucking everything off is a real turnoff.

>>528
you can haz "web access" during installation in CLI mode as soon as you set up networking, anyways.
gentoo.org is properly constructed, so it can easily be viewed with text mode HTTP clients.

>>529
This is good and right. I'm just so used to chrooting that I rarely think to use it.