General Setup

Follow the Gentoo Handbook for installing Gentoo

Generally, you can just use the amd64 version of Gentoo, as most servers now are 64-bit compatible

Here are some general shortcuts/guidelines in the process.

When getting the two tarballs for stage3 and portage, I recommend first retrieving the tarball, then retrieving portage, before extracting either. This way you only have to use links once.
1. run links http://www.gentoo.org/main/en/mirrors.xml
2. Go to releases -> amd64 -> autobuilds and select an appropriate stage3. Hardened is recommended for a server.
3. Go up until you reach the first mirror directory. Go to the snapshots folder and download portage-latest.tar.bz2
4. Extract the stage3 tarball : tar xvjpf stage3-*.tar.bz2
5. Extract portage tar xvjf /mnt/gentoo/portage-latest.tar.bz2 -C /mnt/gentoo/usr
In your /etc/make.conf file, I recommend the following for compile options:
- CFLAGS="-0s -pipe -march=native -pthread""
- Set the MAKEOPTS property to 2x the number of processors/cores, eg, dual core would be MAKEOPTS="-j4"
Set your profile to a server profile, optionally, set it to a hardened server profile.
Compile the kernel using genkernel, as it's less involved than manually configuring everything for the kernel.
Set the hostname to the name of the server

Clang is a faster compiler than the default GCC. It produces binary as fast, or faster than GCC. To set up clang,

run emerge llvm clang

and add these to lines to the top of your /etc/make.conf file

CC=/usr/bin/clang
CXX=/usr/bin/clang++

If a package fails to compile with clang, you can comment out those lines, and recompile the package with GCC.