This has to be one of the shorter prayers out there, but the more I pray it, the more it speaks to me. If you are struggling in your prayer life then why don't you start with these words and see how God uses the prayer to bless you.
"Holy Spirit, come into my heart, and in your power, draw my heart to you." - Catherine of Siena
As you read this prayer it can be tempting to think "is that all?!"
That was my first reaction to be honest. However, I kicked myself for being proud and so I looked at the prayer again. The second and third times I prayed Catherine's prayer it began to impact my heart. Why don't you try it too?