After trying several times and looking around Google, forum etc to find a better and working way to install Elementary Tweaks on my Elementary OS Freya Beta 1, finally I can install it on my EOS Freya Beta 1. It still buggy but at least I can run and use Elementary Tweaks on my Elementary OS Freya Beta 1. I was failed at the first attempt using the ordinary way. But this method is saving my day. Thanks to anybody who wrote this post.
Install Elementary Tweaks on Elementary OS Freya Beta 1 (Works)
Open Terminal and use the following commands:
sudo add-apt-repository ppa:bmeznarsic/tweaks-freya
sudo apt-get update
sudo apt-get install elementary-tweaks
Now open System Settings and click Tweaks