Guide books for young ladies are cool because not only do they cover many aspects of everyday life/common beliefs & societal attitudes most amature enthusiasts/period piece writers, like my self, are inherently drawn to, they also already assume the reader is on some level ignorant of these subjects and therefore (usually) provide more detailed explanations.
I wouldn't really call any one of these early examples a 'conduct book' since I feel like those (at least nowaday) are primarily associated with victorian etiquette guides, which, the works listed below contain little to no etiquette advise whatsoever (in comparsant to other topics). A lot of them sit in this weird cultural limbo were they feel almost victorian but always come short. For one thing, the servants are still considered 'family' in most of these.
This post will list and briefly describe the contents of the guides I've previously used in my own research. I have more of them on my 'shelf', however I haven't read them
Letters to Young Ladies on their entrance into the world c. 1824
✦ Being chiefly concerned with the moral education of its readers, the book primarily reflects the values of the time as well as the ideal for every stage of a woman's life (daughter, wife, mother, spinster/widow). There're also morality tales in the back to show what not to do. It's a bit of a dull read, the author does experiment with metaphor now and then, however, it's also the only one of the books mentioned I'd recommend reading cover to cover (or at least up to the morality tales section). The letters follow a clear trajectory and I feel like reading them out of order would hinder the experience.
Also, Letters to Young Ladies probably has the most detailed advise on choosing a husband out of all of these.
Click here to read Letters to Young Ladies on their entrance into the world
The Young Woman's Guide to Virtue, Economy, and Happiness c. 1818?
✦ It does briefly touch on the subjects of raising children and female virtues, but I wouldn't say that's the main seling point of this one. Aimed primarily at the "lower orders of the middling life" it does apparently have a broader audience in mind too (there's a section with advice for female servants). There are plenty "useful receipts" to be found here on anything and everything - from removing a ring from a finger or writing receipts for rent to home brewing and dying wool. A lot of information on cooking and dinners in general. There's also a lot of random crap that's seemingly been put there just 'cause:
The writing is very disgestible, plenty of examplary anecdotes which truly enliven the reading experience.
Click here to read The Young Woman's Guide to Virtue, Economy, and Happiness
Domestic Duties c. 1825
✦ This one is the most conduct-book-like. It's structured like a series of dialogs between a recently married Mrs L and Mrs B - her older, more experienced friend. The dialogs are devided by topic. Notably, the books describes the first few weeks after marriage, the customs surrounding marning calls, dinners ect. There's a section on lying-in ??if you need that kind of information?? Also, there's sponsored content here???
Click here to read Domestic Duties
There way more of these guide books, of course, if you look for them. And when it comes to the 18th century receipt books can certainly be found, and for moral education there're, like, Fordyce's Sermons (I know they're a classic, I just haven't read them. I've only listed the books I've actually read.)
Seymar, William. (William Seymar is a pseudonymous anagram for William Ramsey.) Cf. Halkett and Laing
Conjugium conjurgium: or, some serious considerations on marriage. Wherein (by way of caution and advice to a friend) its nature, ends, events, concomitant accidents, &c. are examined. By William Seymar Esquire.
London: printed for John Amery at the Peacock over against St. Dunstan’s Church in…
Besure don't let People's telling you you are pretty, puff you up: for you did not make yourself, and so can have no Praise due to it for you. It is Virtue and Goodness only, that make the true Beauty. Remember that, Pamela.