What you are lacking seems to be a bit of empathy and different points of view in this scenario. You are assuming everyone shares the same opinion about this topic:
- Women will have a baby at one point or another
- Women will spend their time, and thereby life together, with a man
- Women are actively selecting men like pieces of meat at the butcher
- Women are only seeking a high income from men
- Men who are not earning a lot will earn more than anybody else later in their life
- Men are seeking to get something, like a philosophy, that will help them make more money than other men
You are making a lot of assumptions that are not necessarily true. Of course there are differences depending on the society you are living in and the social circles that you are living in. But those are the things that stick out to me (and @ItWasLikeThatWhenIGotHere; some of the examples above were named first by that user).
Basically what you need is a different perspective. Ask people you know about their opinion. Do they think the same? What sticks out when they are reading these sentences? What comes to their mind when reading it out loud?
By identifying your assumptions that others may not share you can then proceed to either eliminate them or mitigate some of the things so that it won't alienate your audience as much as your original text. The main thing to look out for is absolutes:
- "The biggest mistake" -> being with someone that doesn't make a lot of money may not be regarded as a mistake by others; to makes this less crass you could change this to "One of the biggest mistakes" so that it will still carry a lot of weight, but the exact placement on the personal list of things not to do is up to the reader
- "have a baby with the wrong guy" -> not every woman wants to be with a guy (or have a baby, but your article seems to focus on the baby part so I will leave that one to you); "have a baby with the wrong person" makes this more abstract, so that more readers might feel related and at the same time you are not imposing your own worldview on the reader; generalizing it is not inherently a bad thing that should be eliminated
- "in the selection process" -> men are not objects that can just be chosen, they have an opinion, too; "when getting to know someone" makes this an equal thing where both parties have something to say in the matter
- "rest of them" -> this implies that the person will automatically be on the top once he got it (I don't know what you mean with getting it, but I assume that's part of that article, so I will leave that one out, too); "many of them" just pushes the person in the upper half or so and leaves the details to the reader
The problem with your original sentences is that they are imposing your own worldview as generalizations of how society has to work. These examples show you a different point of view that would probably help to mitigate some of it if you are aiming for a wider audience.
But: be careful about this. If your target audience is straight female, wanting a baby, looking for a guy to bring in the money then your text is perfectly fine. My examples would work if I, or people from the social circles that I am part of, were your target audience. Is this what you want?
Generalizations are not inherently bad, but you have to be careful with them and the general process of getting rid of generalizations that might alienate your audience is to give examples to someone who is part of or at least close to your target audience and letting them point out where they can identify an opinion they do not share. After that you can try to change certain parts of your text to make them less extreme or more extreme, depending on the feedback you got.
If you are looking for generalizations to get rid of them because you identified that you are prone to getting them not quite as you intended: have a look out for absolutes like "best", "worst" , "all", "none" or "everyone" as well as whole groups like "women", "men", "guys", "kids", "elderly" or "millenials". These are markers that show you where you might be generalizing in a way that your audience may not appreciate.