How to Build a Positive Relationship with Step Kids and Their Mom?

I see often on here a lot of moms aren't too crazy about their step kids and the age varies from kids to teens. While I've never been an official step mom , up until my current relationship I've only dated guys who had kids not purposefully but it just happened that way. All of their kids have loved me from pretty much the start they were never older than about 4-5 when I met them but still I think it's because I treated them like I treat and would want my own treated by a girlfriend or step mom. One relationship I met their child when she was 2 and til this day 10+ years later and with him now having three kids we are very close he is still like a father to my oldest and I am an extra mom to his three two of which were born AFTER we broke up. I'm even close with the mother of the children. We all just recognized the kids were main priority and decided that because our relationship brought them together we wouldn't break their bond. our situation is unique but I think when the other parent(usually the mom) can see that you really genuinely care for their kid there is less drama. Most of the time I notice some of the adverse feelings towards the step kids is linked to the not so good relationship the wife/gf has with the mom. They think any negative thing the child does or says is a result of something the mother has told the child rather than the fact that kids will be kids and try the authority of someone new. I've had moms do lil petty stuff but I never let it get to me and I continued to show the kid love and support and if it was too far crossing the line I had the dad address it. but eventually the mom came around because I killed them with kindness never let the snide comments they related thru the child upset me I knew it was more so mama bear not wanting anyone to "take her place" I never tried to be their mother just someone who was there for them. Never over stepped my boundries. I notice some moms try too hard to be a mom to someone else's kid just let it flow naturally. Children can sense when you being genuine or just putting on a front and they will act accordingly. I think i know what im talking about because til this day years later my ex's with kids that I don't see anymore say that every that every so often their kids ask about me so I definitely left a lasting positive impression. So Step Moms and future Step Moms take your time , get to know the child, treat them like your own, keep an open mind when dealing with the mom don't let the dads negative opinion of the mom effect how you deal with her because that is HIS experience not yours so don't allow his experience to dictate your attitude towards the mom if you are on the defense she will be also. Actions speak louder than words she will See thru how her kids come home and talk about you how you really feel about her kid. Don't try to one up her this ain't a competition it's about what's best for the kids. Don't compare your kids with the others because they are different and raised different.