BE SPECIFIC AND INTENTIONAL
No 1 rule is to be intentional and specific of the reason for the fast.
To be intentional means you are expecting to hear from God, see visions, dream dreams etc so get a notebook in expectation, open a blank page on your iPhone notes in preparation for what He will say or show you.

Fast and PRAY
Fasting without praying is a hunger strike! Your fasting takes on significance when you couple it with prayer. It is time that you've decided to seclude yourself, put your body under so that you can spend more time in seeking God! It is a sacrifice that changes YOU not God!

Listen to sermons and gospel music
Fasting is a time where we are separated onto God even more intentionally to focus on a particular area of development, it is VERY PROFITABLE to "bombard" yourself with sermons and gospel music as often as you can. When you're walking, driving, at your desk and you're not praying or in useful conversation...commit to serenade your spirit man with the efficacy of a solid sermon or be captured by heavenly jamz!

Study your Bible
Spend extra time in the Word of God. Read more, listen more, study more, etc. This will be a good time to embark on reading through the letters of Apostle Paul to the churches (from Romans to Hebrews). Jesus said man shall not live by bread alone...but by every Word spoken by God.

Meditate on a scripture for that day
Out of the abundance of what you READ, choose something to meditate on and hopefully also memorise. Whatever we focus on we become! To help the mind focus on the right things, receive a verse or two that you will keep thinking on and about for the whole day. It may be something that instructs  you directly or a scriptural truth that encourages your soul! 
One of the best ways to make this practical is to use this verse in conversation with friends or in the prayer moments that you've decided. Let the Word of God be your focus.

Do away with common distractions
Moderate the time spent on TV and Social Media and avoid idle talk & banter. Fill up those times with meditation and listening to gospel messages and songs.

Keep hydrated/warm
Due to weather conditions at this time of year take a glass of water, tea or coffee only when necessary during the fast to keep warm/hydrated. Be careful not to overdo this as you could feel quite heavy and unable to concentrate on the fast.