dircolors for better ls listing

ls uses the environment variable LS_COLORS to determine the colors in which the filenames are to be displayed. This environment variable is usually set by a command in the .bashrc file like
eval 'dircolors some_path/dir_colors'
to create a customize .dircolors file, use the command

dircolors -p > .dircolors

and then edit the .dircolors file.

for example, change the color of execute permission to red with: EXEC 00;31

The comments in the generated .dircolors file already listed the color codes.
ISO 6429 color sequences are composed of sequences of numbers separated by semicolons. The most common codes are:

Attribute Codes:
00 none — to restore default color
01 bold — for brighter colors
04 underscore — for underlined text
05 blink — for flashing text
07 reverse — to reverse background and foreground colors
08 concealed — to hide text
Text Color Codes: Background Color Codes
30 for black foreground 40 for black background
31 for red foreground 41 for red background
32 for green foreground 42 for green background
33 for orange foreground 43 for brown background
34 for blue foreground 44 for blue background
35 for purple foreground 45 for purple background
36 for cyan foreground 46 for cyan background
37 for gray foreground 47 for gray background
Extra Text Color Codes: Extra Background Color Codes
90 dark gray 100 dark gray background
91 light red 101 light red background
92 light green 102 light green background
93 yellow 103 yellow background
94 light blue 104 light blue background
95 light purple 105 light purple background
96 turquoise 106 turquoise background
97 white 107 white background

Reduce the Size of Icons on GNOME Dash

Edit /usr/share/gnome-shell/js/ui/dash.js

Change

...
const Dash = new Lang.Class({
    Name: 'Dash',

    _init : function() {
        this._maxHeight = -1;
        this.iconSize = 64;
        this._shownInitially = false;
...

to

...
const Dash = new Lang.Class({
    Name: 'Dash',

    _init : function() {
        this._maxHeight = -1;
        this.iconSize = 32;
        this._shownInitially = false;
...

and further down the script

...
let iconSizes = [ 16, 22, 24, 32, 48, 64 ];
...

to

...
let iconSizes = [ 16, 22, 24, 32 ];
...

Logout and log back in to see changes.

Reduce Applications Icon Size in GNOME Shell

Edit /usr/share/gnome-shell/theme/gnome-shell.css

...
/* Application Launchers and Grid */

.icon-grid {
  spacing: 36px;
  -shell-grid-horizontal-item-size: 118px;
  -shell-grid-vertical-item-size: 118px;
}

.icon-grid .overview-icon {
  icon-size: 96px;
}
...

to

...
/* Application Launchers and Grid */

.icon-grid {
  spacing: 18px;
  -shell-grid-horizontal-item-size: 96px;
  -shell-grid-vertical-item-size: 96px;
}

.icon-grid .overview-icon {
  icon-size: 48px;
}
...

Logout and log back in to see the change.