You can use tellraw (and other JSONish commands as /title etc) command generator, located here: Minecraft JSON generator
You can pick colors from color picker and add text pieces as you need. It also has preview visible when you add new parts of text. You can also choose the styles and click events for each piece of text.
Look at the outputted code for learning how added pieces of text influence the command.
Don't forget to use commandblock for too long commands. Enjoy.
