My tmux.config file that I've pieced together based on others.

.tmux.conf

# status bar
set-option -g status-utf8 on

### COLOUR (Solarized dark)

# default statusbar colors
set-option -g status-bg black #base02
set-option -g status-fg yellow #yellow
set-option -g status-attr default

# default window title colors
set-window-option -g window-status-fg brightblue #base0
set-window-option -g window-status-bg default
#set-window-option -g window-status-attr dim

# active window title colors
set-window-option -g window-status-current-fg brightred #orange
set-window-option -g window-status-current-bg default
#set-window-option -g window-status-current-attr bright

# pane border
set-option -g pane-border-fg black #base02
set-option -g pane-active-border-fg brightgreen #base01

# message text
set-option -g message-bg black #base02
set-option -g message-fg brightred #orange

# pane number display
set-option -g display-panes-active-colour blue #blue
set-option -g display-panes-colour brightred #orange

# clock
set-window-option -g clock-mode-colour green #green

set -g status-interval 1
set -g status-justify centre # center align window list
set -g status-left-length 20
set -g status-right-length 140
set -g status-left '#[fg=green]#H #[fg=black]• #[fg=green,bright]#(uname -r | cut -c 1-6)#[default]'
set -g status-right '#[fg=green,bg=default,bright]#(tmux-mem-cpu-load 1) #[fg=red,dim,bg=default]#(uptime | cut -f 4-5 -d " " | cut -f 1 -d ",") #[fg=white,bg=default]%a%l:%M:%S %p#[default] #[fg=blue]%Y-%m-%d'

# displays *
unbind *
bind * list-clients

# next Space
unbind " "
bind " " next-window

# prev BSpace
unbind BSpace
bind BSpace previous-window


# C-b is not acceptable -- Vim uses it
set-option -g prefix C-a
bind-key C-a last-window

# Start numbering at 1
set -g base-index 1

# Allows for faster key repetition
set -s escape-time 0

# Rather than constraining window size to the maximum size of any client 
# connected to the *session*, constrain window size to the maximum size of any 
# client connected to *that window*. Much more reasonable.
setw -g aggressive-resize on

# Allows us to use C-a a <command> to send commands to a TMUX session inside 
# another TMUX session
bind-key a send-prefix

# Activity monitoring
setw -g monitor-activity on
set -g visual-activity on

# Highlight active window
#set-window-option -g window-status-current-bg red

# Vi copypaste mode
set-window-option -g mode-keys vi
bind-key -t vi-copy 'v' begin-selection
bind-key -t vi-copy 'y' copy-selection

# hjkl pane traversal
bind h select-pane -L
bind j select-pane -D
bind k select-pane -U
bind l select-pane -R

# reload config
bind r source-file ~/.tmux.conf \; display-message "Config reloaded..."

# auto window rename
set-window-option -g automatic-rename

# rm mouse mode fail
set -g mode-mouse off

# windows ^W w
unbind ^W
bind ^W list-windows
unbind w
bind w list-windows

# quit \
unbind \
bind \ confirm-before "kill-server"

# color
set -g default-terminal "screen-256color"

# allow pbpaste and pbcopy commands to work by promoting the tmux server process to
# a higher namespace (root)

# only enable this if you've got this binary installed.
# it is available as a homebrew package
# `brew install reattach-to-user-namespace`
# i happen to use zsh so you'll probably want to do -l sh or -l bash
# set-option -g default-command "reattach-to-user-namespace -l zsh"

bind @ kill-pane -a

# resize panes like vim
bind < resize-pane -L 10 
bind L resize-pane -L 100
bind > resize-pane -R 10
bind R resize-pane -R 100
bind - resize-pane -D 5
bind D resize-pane -D 36
bind + resize-pane -U 5
bind U resize-pane -U 35

tmux.conf.md

I'm probably missing a link or two in my credits, but I know for sure that I shamelessly borrowed from the following:

• tmux.config
• tmux.config