Having the right perspective while praying for your future spouse is very important. Do not let stress or anxiety overwhelm you, but put your value system in order.
"Seek first the kingdom of God and his righteousness, and all these things will be added to you." Matthew 6:33
Use your "freedom" as a single to grow spiritually and increase dependency on the Lord, because you will need it as you weather various seasons in your marriage. You would want your future spouse to be doing the same thing. Also use this time to diligently serve the Lord in furthering His Kingdom, as there is nothing more rewarding than this.
God is in charge of your life. He knows you better than You know yourself and knows what you need. So instead of making a "list" of what you want in your future spouse, seek the Lord and His Kingdom first. The one who has the same priorities as you is the one that will keep you on the right track in life.
There was a reason why the Lord taught us to pray, "and lead us not into temptation". For singles, sexual temptation abounds especially in a generation that has degraded sex to a casual activity. This is all the more reason to seek divine protection and strive to keep your mind and body pure.
I don't' know who You have prepared to be my future husband/wife, but You know, so I entrust my life to You.
Let me not be anxious, but continue to come to You in prayer and supplication with a thankful heart. Let the peace of God, which surpasses all understanding, guard my heart and mind in Jesus Christ. (Phil4:6-7)
Keep me from wavering and land me stand firm in faith and hope.
In Jesus' name, Amen.