To be contrarian to other answers: In a male dominated society, allow males to have harems of up to 10 wives, and to own as many concubines as they wish (none of which are allowed to become pregnant; if they do, the pregnancy is aborted).
Allow females to be sold (e.g. the Bible explicitly offers advice to men on how to price their daughters). Allow early testing for male/female fetuses, and insist that men have no more than two male heirs, but can have as many female offspring as they wish, and can sell these girls to other men.
If any additional male heirs are not aborted, and are brought to term, they become slaves for life. Many more women than men will be produced; so the ratio of men to women will remain 1 to 10 or more.
Late add: To address issues brought up in comment (which was moved to chat):
I am being contrarian, IMO the OP was fishing for ways to elevate women; I think there is a way to achieve the result by doing the opposite. I read the Bible, and although I do not believe in any God, I do believe it accurately portrays a real and stable society in which women are property: There are numerous examples of sexual slavery, the selling of women, permission to rape servants and so on. Such societies are not impossible or unstable.
Better access to healthcare: I presumed if women were treated as livestock then they would have a monetary value and it would be in the best interest of their owners (men) to keep them healthy. For the same reason, IRL in America, race horses get far better medical care than homeless people, and millions of pet dogs get better medical care than homeless people. Of course the author could still making the killing of a female illegal, or give females some limited set of human rights their owner must provide, to whatever extent the author wishes.
Better access to education: I admit I forgot this part! However, it follows naturally from my premise: if 90% of the population is female and owned by males; they are going to be doing all the work; including the work that demands education. As IRL, rich men in this society would be running things as managers; they would not be the engineers, technicians, nurses, doctors and so on in the society; or at least the majority of workers in this society would be females. That requires education. Since higher education results in greater value; it is in the best interest of a male to get his females as educated as possible, for future sale or lease as workers.
If women are in charge of everything, the have a great deal of control over what men see and how events are interpreted. They are probably the soldiers and managers of companies, the military, and government agencies. Just because they are not the CEOs of those operations does not preclude them from wielding significant levels of power to shape their society.
- Slavery of Excess Male Offspring: I'll just abandon this idea in favor of a better one I had: All offspring must be examined at birth, any males brought to term beyond the legal limit of two would be humanely sterilized; perhaps by amputation of the testicles. The father is still responsible for caring for such males for life; but they will not be allowed to marry or take wives. Upon examination and verification that an infant is female; the female can be "marked" by permanent tattoo, or alternatively a long-lasting dye, like those used in some countries to indicate that a person has already voted: The reason for this is to prevent any substitution of a recently born female infant for a male infant. Even a man with minimal training can tell the difference between a 1-day-old infant and a 7-day-old infant; so no female can be examined twice to hide an extra male heir. Further, any man caught trying to do this can be stripped of all of his property and sterilized.
The point of this is to maintain the ratio of men to women at 1:10, the men are in charge but it takes 10 women to support each man. Additional population controls can be instituted if necessary to control the population and retain this ratio; e.g. only a single male heir is allowed.
Alright, I'm done with this exercise in thinking outside the box; and that is all it was, a stray rebellious thought to answer the question. Based on the tone of some comments, I encourage people to remember that me writing about fictional slavery, rape or murder does not imply I am pro-slavery, pro-rape, or pro-murder!
Note this question had three requests: First that a country must favor girls in birth ratio or prefer that girls be born, then secondly and thirdly the uncorrelated requirements that girls have "better" access to healthcare and better access to education. Those conditions do not go hand-in-hand, but I am interpreting "better" to mean more certain than that of many women IRL.