I am currently struggling with Lukewarm interest in nearly every area a Christian can. I am trying various means to overcome, and I have no doubt that I shall. However, I am familiar with the Laodicean church in Revelation 3:14-22 who was commanded to overcome by returning to the practices that first ignited their spiritual fire. This can not work in my case because fear of God's rejection led to my initial commitment to following Him, but now I've overcome that fear and rest in Jesus's completed work while keeping myself from sin.
I suppose I'm asking what else I could be doing.
I would seriously think about how much you love God. I know this sounds very open ended, but Jesus left us with the MOST important commandment to love the Lord your God with all your heart, soul and mind.
Usually (and I am saying usually) those who are lukewarm are doing things "FOR" God, but not walking "WITH" God.
Once you love God, it seriously get's so much easier because you want what God wants. You realize that He is your loving Father that knows what is best. Just like when we have children we try to shield them from mistakes, God in His love is trying to remove sin and dispair from our lives.
If you really believe that He is a good, good Father, Abba Father, than you know that He only has good plans for you. Not necessarily plans to make you all that on this earth, but His plan for you is the heavenly things and becoming more like His Son and that is eternal. That you will take with you.
God becoming your best friend, since He is perfect, is a joy. Putting things and leaving problems at His throne and entering His rest in faith that all will be just as it should be, is a true rest for the weary soul.
Seek the spiritual things and then "all of these things will be added unto you".
One last consideration is know who you are in Christ. The Father, God Himself, sent His Son, God Himself to die for you so He could have His creation back. Not only does He get you back, but He has made you a Child of God. A son or daughter, an heir to God and a co-heir with Christ to the Father. You have your downpayment of your heirtage now, in the Holy Spirit residing in you forever. Your future is bright. Don't forget who you are and what God did to get you back.