At 13 months old she doesn't need milk at nighttime. It helps to know that when you're starting off.
For night weaning, set a time that you're definitely not going to feed before and then set intervals. Adjust for your bedtime but I'd go as follows;
7pm bed, nothing before 3am and then nothing again until 7am. Either that or just nothing at all at nighttime. It will be painful but relatively short! 7pm and 7am only. With your 3am feed, if you do it, time it on night one and reduce by a few minutes every other night until it's down to nothing. Once you've finished, the night bar is closed and NO MORE MILK. You'll need some of your dd's willpower!
Once you've set your rules you have to devise a plan of how you're going to get her to sleep. I would do a nice but short routine of bath, if it's a bath night followed by pjs, milk, book, teeth and then bed. We do the majority of our routine downstairs and this started by having no milk in the bedroom. We just read 3 books, always the same ones that live upstairs and into his cot with a teddybear.
I have used controlled crying but appreciate that this isn't everyone's cup of tea. You could try that, gradual retreat, cry it out. You are likely to have some crying but babies do adjust quickly and she may be more ready for a bed now.
I hope this isn't too much to take in - good luck!
We night weaned and apart from a few rocky months relating to teething, DS has mainly slept through since then.