My tmux config (compatible with Tmux v2.3+)

.tmux.conf

# remap prefix to Control + a
set -g prefix C-a

# bind 'C-a C-a' to type 'C-a'
bind C-a send-prefix
unbind C-b

# Allow to scroll and resize panes with mouse
set -g mouse on

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

# Set escape time for Vim
set-option -sg escape-time 10

# Start new window in current directory
bind '"' split-window -c "#{pane_current_path}"
bind % split-window -h -c "#{pane_current_path}"
bind c new-window -c "#{pane_current_path}"

# Start windows and panes at 1, not 0
set -g base-index 1
setw -g pane-base-index 1

# Change color scheme. Credit goes to http://www.hamvocke.com/blog/a-guide-to-customizing-your-tmux-conf/
# Status bar
set -g status-position bottom
set -g status-bg colour234
set -g status-fg colour137
set -g status-attr dim
set -g status-left ''
set -g status-right '#[fg=colour233,bg=colour241,bold] %d/%m #[fg=colour233,bg=colour245,bold] %H:%M:%S '
set -g status-right-length 50
set -g status-left-length 20

setw -g window-status-current-fg colour81
setw -g window-status-current-bg colour238
setw -g window-status-current-attr bold
setw -g window-status-current-format ' #I#[fg=colour250]:#[fg=colour255]#{b:pane_current_path}#[fg=colour50]#F '

setw -g window-status-fg colour138
setw -g window-status-bg colour235
setw -g window-status-attr none
setw -g window-status-format ' #I#[fg=colour237]:#[fg=colour250]#{b:pane_current_path}#[fg=colour244]#F '

setw -g window-status-bell-attr bold
setw -g window-status-bell-fg colour255
setw -g window-status-bell-bg colour1

# Messages
set -g message-attr bold
set -g message-fg colour232
set -g message-bg colour166