Welcome back. After designing the circuit using adafruit's lovely tutorials, the next step is to build it. I have attached a photo of what the circuit looks like in real life. A few points about why I chose to do certain things.
1. Wire Colors: Using different colors for different wires makes building your circuit and looking for problems much easier. I would suggest using differently colored wires for specific purposes. That way, when you look at your board, you know what wires are supposed to go where and can more easily identify problems. Here is the color scheme that I am using:
Red: I always use red wire for 5 Volt power. If it's red, I know that it's a 5V signal.
Brown: Brown wire is my 12 Volt power coming from my 12 Volt power supply.
Black: I normally use black wire for ground. In this case, I am not using negative voltage, so all black wires are ground.
White: I usually use white wire to transmit signals from the arduino and for my resonator.
Yellow/Green/Blue: This is a generic color for transmitting signals. Normally, as long as two adjacent signal wires are different colors, then it's ok. Normally, I use wires in (sort of) the following order: White/Yellow/Green/Blue. For this project, I chose green, yellow and blue to transmit the signals to my TIP120's so that I know what wires are going out to control each part of the RGB LED's. I can't use red as a signal wire, because I only use red for 5 Volt power.
Note: I didn't show the input power and the wires going to the RGB LED's in the picture below. There are, however, wires sticking up where I will put the RGB wires. The input power is unmarked, but has a brown wire on it already to remind me where it goes.
2. Resistors: I used 10 kOhm (10,000 Ohm) resistors for my button, and 1 kOhm (1,000 Ohm) resistors for my TIP120's. I do not need very much current for buttons, and the TIP120's do not need very much current to turn them on.
3. Capacitors: I used two capacitors for my voltage regulator. This helps to smooth out voltage spikes, which will occur as I turn the LED's off and on quickly. I used the capacitors that I had sitting around. Normally, I use the circuit described in Make: Electronics by O'Reilly. That has a 0.33 microFarad electrolytic capacitor on the input voltage and a 0.1 microFarad ceramic capacitor. If you are interested in learning about the basics of hardware, that is a great book to pick up. The capacitors I had were a little bigger, but it should work fine.