A good basic tmux config

.tmux.conf

# Optional: Set shell
# set-option -g default-shell /bin/zsh

# For neovim to use the <esc> key faster
set -sg escape-time 10

# Set the base index for windows to 1 instead of 0
set -g base-index 1

# Set the base index for panes to 1 instead of 0
setw -g pane-base-index 1

# Reload the file with Prefix r
bind r source-file ~/.tmux.conf \; display "Reloaded!"

# mouse support - set to on if you want to use the mouse
set -g mouse on

# Set the default terminal mode to 256color mode
set -g default-terminal "screen-256color"


# set the status line's colors
set -g status-style fg=white,bg=black

# set the color of the window list
setw -g window-status-style fg=cyan,bg=black

# set colors for the active window
setw -g window-status-current-style fg=white,bold,bg=red

# colors for pane borders
setw -g pane-border-style fg=green,bg=black
setw -g pane-active-border-style fg=white,bg=yellow

# active pane normal, other shaded out
setw -g window-style fg=colour240,bg=colour235
setw -g window-active-style fg=white,bg=black

# Command / message line
set -g message-style fg=white,bold,bg=black

# Status line left side to show Session:window:pane
set -g status-left-length 40
set -g status-left "#[fg=green]Session: #S #[fg=yellow]#I #[fg=cyan]#P"

# Status line right side -  31-Oct 13:37
set -g status-right "#[fg=cyan]%d %b %R"

# Update the status line every sixty seconds
set -g status-interval 60

# Center the window list in the status line
set -g status-justify centre

# enable activity alerts
setw -g monitor-activity on

set -g visual-activity on