Let’s consider “a good deed”. Any good deed. I may do the good deed because (1) I want to be good by my actions (self-righteousness) or I can do it because (2) I love the party for whom I’m doing it (I think this is the love spoken of in 1 Cor 13). For most of my life, I thought my job was to BE or BECOME “a good person” by doing things that are good not bad (self-righteousness). I’m now growing into the belief that my good-person-status has already been accomplished permanently and unchangeably. I don’t need to work on that any more. Being a good person doesn’t have to be a goal. It’s already accomplished by God’s IMPUTED goodness made possible at the execution of Jesus. I have to work to remember this every day. I forget often. My “default” way of thinking seems to be to try to be a good person.
I don’t think I (or we) can just “decide” to have the love motive for something. I don’t think we are humanly ABLE to decide to have the love motive. I think the kind of love spoken of in 1 Cor 13 (that says that ANY act/deed, even as seemingly “good” as selling all you have and give it to the poor, can be worthless if not a product of love) can only happen TO you when you realize how loved, forgiven, treasured, accepted, etc. you are by God himself and, because of this, literally EVERYTHING in your life is really OK. Once you know that everything in life is really OK, you will be so happy that your true love will splash/spill out of you onto those around you.
If you want to truly love others, you must work on knowing and believing what God says. To the degree you are successful at this, you will love well. You can’t try/work to love others in the way that the word “love” is used in 1 Cor 13. It has to grow out of you without your trying.