This guide shows you howto change the color of the wingpanel. If you wish to have different color than shown in this guide I suggest installing Gimp from the App Center to easily get the RBG numbers.
Open the terminal and copy/paste;
Insert the following;
* wingpanel support *
transition: all 1s ease-in-out;
This will make your wingpanel white transparent. The 3 first number in RGBA is the color numbers. Use Gimp to find the color you want. If you want a black wingpanel, change all 255 with 0. The last number is how transparent the panel is going to be. It range from 0.0 (complete transparent) to 1.0 (Solid).
If you are looking for a way to get rid of the “Applications” text in Slingshot here’s a guide to do so. This guide uses the default elementary theme as an example. Adjust the guide to the theme you use.
This guide shows you how to change the magnifier glass in Slingshot. This example uses (e)papirus icon theme as demostration and it uses the good old elementary logo for the purpose. If you are skilled with inkscape you can make your own.
If you’re using a different icon theme, you need to adjust this guide.
You can now find elementary tweaks in System Settings.
To get more themes to use in elementary OS you need to do following that will make two folders in your home directory. One for your themes and one for your icons:
mkdir -p .themes
mkdir -p .icons
The two folders are hidden, so you need to right click in your file-browser and select Show Hidden Files.
Next thing is to head over to www.gnome-look.org and download a theme and some icons. The icons section is here and the theme section is here. Unpack the icons to the .icons folder and unpack the theme to the .themes.
When it’s done go to System Settings and click Tweak.