In the modern times with easy divorce and especially divorce theft, many young men are very careful about who they put a ring on. Marriage is a big time risk for the fellas; therefore they need to be sure that you are focused for the long haul as a team.
Preparing for selling yourself to a young man should start when young. One should develop the proper attitudes and behaviors such that they become internalized. For pretending to have these when older is very often not effective. Guys are are the lookout for tells that suggest that a woman is not what she presents herself as. With the test of time during the modern version of a courtship, these tells almost aways eventually come out (hence the reason for internalizing them, making them real).
Let us consider some attitudes and behaviors. Note that this list is not all inclusive, commenters are free to add more.
I. Don’t act, think or be a slut; no matter how tempting it is. Being this way makes you a bad marriage prospect.
II. Be truthful with him. Tell no lies. Once he detects a lie, then he wonders what else you are lying about. This does not bode well for a long term relationship based on trust.
III. Don’t have crazy quixotic goals/ideas (especially if he does not have the same). He wants you to be a wife and maybe a mother. Chasing after silly stuff is not conducive tho this.
IV. Have a clue. I once had a friend who chose his wife because she had a clue. That is, she had enough sense about how the world really works to make a practical wife.
V. Make him feel, if not special, at least appreciated.
VI. Be reliable / not flaky. Demonstrate this to him.
These by themselves should get a young lady far. Add away.
Addendum by Deti,
VII. Learn how to take care of living quarters. Learn domestic skills. Cooking, cleaning, child care.
VIII. FFS, if you do not want to fuck the guy, cut him loose. If you used to want to fuck him but you’ve lost that lovin’ feelin’, cut him loose. If you don’t want him, cut him the fuck loose.