So they wasted their most bankable years not getting married and are now closing to the wall, or have just past it (officially at 30, but in practise somewhere between 25 and 35 depending on genetics).
Not sure what n count you consider "low". To me that is n=1-3. But I'm assuming you mean 4-6?
Best way to go about it is to lower standards in how sexy they find a guy (one of the tragedies for women is that every new partner is likely to be less attractive than the last, due to youth and its fertility markers being prime selective pressures) and increase standards with how serious the guy is (even if that is a turnoff, and it usually is for women).
They should be going to places where they meet men. Dance classes, bookgroups, ultimate frisbee, church group. Basicly anything with mixed genders that fits with their own personality. Then they should have fun, make sure to look good going there and if they like a guy, not be afraid to move things along. But when going on dates, make some effort at finding how serious he is. Making some moves is a risky strategy for women, as it allows men who would not date them seriously to take advantage of them (I know I have), but it can help them land good men who are less players (aren't used to hitting on women and therefor; more likely to commit).
Birth control has put a competitive pressure on women to engage in sexual activities (or lose the guy to someone who does). But birth control does not eliminate all the risks (broken heart, pairbonding capacity).
One of the biggest problems for women these days is inflated self-perceived value. Whether the amount of responses they get on dating apps, or the amount of men giving them attention (for sex, not long term relationship). But also because all of their experiences are based on how young she was yesterday, yesteryear etcetera.
Look at someone like leonardo dicaprio who has all the choice in the world. Every girlfriend has been drop dead gorgeous. And everyone got dumped when they passed the age of 24.
There are about 8 women out there who have tasted the best of the best; but afterwards they have to settle for someone less than dicaprio. And less than if they had gone for someone lesser that they could lock down, because now they're 26, 28, 30.
This kind of mistake is made by women across the board.