You asked about davening for women you see on the street or work with at your job who you have a hard time getting out of your mind.
The first business I have with Hashem's pretty women (and shiksas are of course His humans, too) is to have the right relationship with them. And the right relationship with them has nothing at all to do with their breasts, waists, etc. That's clear. She has nothing to do with me at all! She is not mine, anyway. So I can stop pretending she is, that she could be, or would be, and humbly let her go completely. G-d has nothing to do with that, the yetzer hora has nothing to do with that. It's just growing up for a second.
If I am at peace with that, I can just accept they are not mine, their images are not mine and not for me at all. I can surrender them and give up my right to take in their images and lust after them. Not much pain in that.
But if that logical, realistic and calm approach does not work, then it is time for prayer. Not praying for myself or for G-d to help me, though, but praying for them to be healthy and happy, saved from the normal tzaros of life like: losing a child G-d forbid, having a husband who shames them or hurts them or betrays them with affairs (as many of us have), from mental illness or addiction, from poverty R"l or bad debts, car accidents R"l, and other fears and pains of real life. And regarding their inevitable deaths (we will all die one day): How will their last days and moments be? Our deaths are never a party, but please let them have a pleasant end and not a terrifying, lonely, or painful one that many people do have, especially goyim who often have less intact and close families. And most of all, that Hashem care for them by helping them get a relationship with Him, a real awareness of Him in their lives that is the greatest gift.
BY the time we do that, we may be ready to do what I called 'the first business' of letting her go completely.
Praying for the people we don't easily let go of has three effects:
1- it makes them people instead of sex objects. When we insist we are too 'disgusted' by shiksas to pray for them, we are really just insisting on keeping them objects - so that we can still lust after them and use them for porn fantasy in our imaginations. Like Nazi's pretended Jews were sub-humans ('vermin') so that their people could kill us without real guilt. Same here, dressed up as kano'us and 'tzniyus'.
2- it makes them real, frail people instead of the true goddesses we feel them to be and believe they are - for are we not following them around?? That is huge right there, because we chase these women on the computer and on the street, and seek them for a better view of their faces, voices, and bodies because we sincerely feel they are goddesses and powerful, beautiful, precious and badly needed by us. We need to remember they are just frail people as we are frail people, not sex machines, goddesses, or toys for us.
3- it helps us be more like Hashem and love all the things He made and cares for deeply - even the shiksas. What? To love them - gevalt! That's the most dangerous thing! Not so - not if we love truly. By seeing them as His stuff - His people...yes, His shiksas - not mine. As Dovid haMelech said after recounting the birds, hills, seas, men's accomplishments, the rocks, clouds, and rain: Yismach Hashem b'ma'asov! Let Hashem take pleasure in all He made, for He loves (gives Himself to) all that He made, even the shiksas have a purpose. His purpose, regardless of their bechira in how to dress. That is just a distraction to us in their true purpose and value. Each beryah having it's own Purpose like everything here. Appreciating it for it's true place in His world. And I can only do that by davening for it. How else can I, a sexaholic give to or care for her? By hugging her and telling her I like her? Heh. Obviously not. By buying her a coffee? Don't think that'd be a way to give - it'd just be a way for me to use her, of course...then how?! By letting go of her - and if I cannot, then by davening for her sincerely, and moving on. Now that I have restored my relationship with her to a proper state and I can easily let her go - surrendering her image, her, everything about her. None of it has a thing to do with me, really. That is loving her. Like the Shalo"H says that by not eating chazer (pig), we have the proper relationship with it and fix it. He says that is why it is called "chazer" - it will go back to becoming kosher because of our tikkun by not eating it, living the right relationship to it. Hating pig is not mesaken anything at all - as the RMB"M clearly writes, "One should not say "I detest pig, so I do not eat it" - rather he should say "I'd like some but Hashem says no."" True Love is having the proper relationship to my wife, to you, to the shiksas in the street, to my parents, to the people that annoy me in shul or yeshiva, to my boss, my kids, to everyone and everything. It's how to love them all - how to connect to them all properly. It's Da'as...connection. The mental part ('moach') of the middah Yesod (connection). The tzaddik that Chaza"l say is all about 'achid Sh'maya v'ara'.
And Love - true concern through prayer and behavior - is the very opposite of Lust and neutralizes it's power - even the lust in bed with our wives, b"H. For if we insist on keeping erotica in the bedroom, we will keep it everywhere, even in the street. The proper relationship to everything and everyone allows us to do what Tzaddikim do: Achid Sh'maya v'ara - connect everything and everybody around them (even the shiksas, goyim, trees, fish, dirt, etc) to Hashem. Even though we are very far from being anything like 'tzaddikim'. We accomplish that through our sick-ness rather than through ur good-ness. And that's OK.
It also helps us chill and just be. To live life without going crazy over noticing a desire in us and having to quick stamp it out, struggle and wrestle with it to the death. Oy gevalt. We give the little distractions from real life so much life by making it a big struggle. Better to recognize it, surrender it and pray for the person we have a problem with, whether it be a lust, a resentment, whatever. For there is no sin anywhere in Torah sh'bichsav or Torah sh'b'al peh that says it is a sin to have desire - the only sin is harboring it. Sadly, we have long preferred to hold onto it by struggling with it, and railed against giving it up. Surrendering it is badmouthed as 'abdicating bechira', 'not winning the nisayon', etc, etc...all exaggerations and nahrishkeit'n. Our terutzim are just ways to lock ourselves in an embrace with it, with her image, with the idea of masturbation or of porn as long as possible, by wrestling with it - 'fighting' it...nu.
Boruch Hashem there is a better way! And the 2nd and 3rd step are one straight path to it for many.