"Do not fret or have any anxiety about anything, but in every circumstance and in everything, by prayer and petition (definite requests), with thanksgiving, continue to make your wants known to God" - Phillipians 4:6 (AMP)

God has a recipe for prayer:  don't worry - pray; have definite requests.  Afterwards, keep thinking Him for the answer to that request.  A definite request is a formal written request.  God is serious about this prayer business and expects us to be also. 

I exhort therefore, that first of all, supplications, prayers, intercessions, and giving of thanks, be made for all men; for kings, and for all that are in authority; that we may lead a quiet and peaceable life in all godliness and honesty.  For this is good and acceptable in the sight of God our Saviour. - 1 Timothy 2:1-3

in these verses the Apostle Paul is clarifying what types of prayers believers should pray, as well as, for whom we should be praying.

And the men turned their faces from thence, and went toward Sodom:  but Abraham stood yet before the Lord.  And Abraham drew near, and said, Wilt thou also destroy the righteous with the wicked? - Genesis 18:22-23

Call to Me and I will answer you and show you great and mighty things, fenced in and hidden, which you do not know (do not distinguish and recognize, have knowledge of and understand) - Jeremiah 33:3 (AMP)

"Fot the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds" - 2 Corinthians 10:4