Download and install Go tools

There is an OS X package to make life easy:
https://golang.org/dl/

Setup Go workspace

mkdir $HOME/go
cd $HOME/go
mkdir bin pkg src

Setup Go environment

sudo vi ~/.bash_profile
export GOPATH=$HOME/go
PATH=$PATH:$GOPATH/bin

Create, build and run a Go project

mkdir $GOPATH/src/github.com/todsul/hello
touch $GOPATH/src/github.com/todsul/hello/hello.go
go install
hello