When starting this game most of it seems pretty simple. You follow the hints in the quest book and things should work out. However, there is A LOT of grind in this game in the beginning.

It may be beneficial in the beginning to decide how you want to play. Just picking up the game and playing around to see what happens can be ok but you'll be locked out of a lot of content unless you get serious about improving your character.

There are a lot of things to do in this game and unlike what the title of the game suggests they don't all revolve around the ladies in your life. You can if you really want to just ignore the ladies and focus on other things.

So here are some suggested play styles for beginners.

First decide if you want to use the New Game Plus system or start each character new with zero stats and zero money.

1:New Game Plus
Star a new character (0 stats and 0 money). When creating your character while talking with Bree and Sasha at the beginning you need to pick Work and Don't Sleep. From day one you can buy the luxury bed. There is also the option to get sneaky but I don't know what that does. Either way, the opening dialog is the only way to get that skill.

Don't buy the charm machine. It is a waste of money.
Other skills that you can acquire during your first playthrough are:
Cooking: Book at the book store
Massage: (I never use this anyway) book at the book store
S&M: Book at the book store
Shibari: Book at the book store
Go Kart: Race many times at the Go Kart Track
Martial Arts: Beach during summer. You have to buy a car. It might be ok to skip this and get it through dialog on the next playthrough.
Dancing: Learn from Palla in her story but also you can skip this and learn it on another playthrough during character creation.

Skills you have to get through dialog as there are no options in game to learn them diagetically.
Shooting
Iron stomach
Hung
Lucky (not sure it counts as a skill but it does change the game)
Gamer


Ignore the ladies. You have three stats you can improve. Seriously, AVOID THE LADIES.
Avoid improving charm. Instead improve knowledge. You will bump into Kylie at the University but if your charm is low it doesn't matter because to unlock her you have to bump into her again when your charm is high. So with a low charm character get all your knowledge points at the university and then never go back there.

Go to work once a day and the rest of the day go about maintaining your needs, learning skills, and improving knowledge. Once knowledge is at 100, move over to Fitness. Once your muscles are at 100 then you can improve Charm.

Charm can only really be cheaply and reliably improved by drinking booze at the night club so buy some fancy clothes and then make make a schedule. Wake up at 6, shower, eat breakfast. Work at 8. finish work at 12. Run around and compliment anyone who is in the game except Kylie if you happen to accidentally unlock her. (AVOID KYLIE. She can murder you and then it is game over with no new game plus). Set your alarm to 2200 and sleep. Wake up at 2200. Shower and eat dinner. 000 go to the night club and be a drunk. 2:00 go home and sleep until 6:00. Repeat until Charm is 100.

Once you have all your skills and full stats you can alter your schedule to maximize money.
Every so many times you go to work you will earn points towards a raise. There is no cap on the raises. If you happen to go to the office party then you put your job in jeopardy and no other job in the game will get you rich like the office job.

6 Wake up, shower
7 Breakfast, maybe coffee or skip the coffee and save it for later
8 work
12 finish your first shift, compliment all the girls in the game until fun is maxed. coffee in the break room. Also, coffee at home. 5 dollar hot dog in the mall. Finally, work again.
16 Take out your phone, send text messages to all the girls until fun is maxed again. Work a third time
20 Dinner with roommates
21 Shower
22 Video Games
23 Sleep

That is your day until you have a million dollars. Your character should be able to do that schedule most days but the ladies will interrupt you and inject their stories into your life. That is ok. We're not trying to do a perfect no interruption run, just get to one million dollars without Kylie murdering us.

Honestly, you can probably get to about 60,00 and then you have plenty of money for any subsequent playthroughs. But I like a million because once you get the office going and the big money starts rolling in it doesn't make sense to go back to earning 30 dollars for a shift of work until I'm at the point where working is completely optional in the game.

Also, do not go to the office party. Let Aletta be mad about it.

Once you have all stats and skills and money that you want for the start of the next playthrough, pick one of the girls that you can marry and then buy a wedding ring. Getting married ends the playthrough and saves your data to start a new character.

2: Second characters from New Game Plus
Once you've finished the grinding with the first character and you've started a second character I suggest picking one girl and playing through her story to the end. If she can not be married then go date up one of the marriageable girls and finish that playthrough. Each time you go around you will notice that the options at the beginning become fewer and fewer as you take all the skills. Eventually you'll have all of them except for the two that exclude each other.

3: NOT USING NEW GAME PLUS

Well, I hope you like grind. (seriously there is a lot of grind) See the above and then once you have one million dollars pick a girl and ...

Oh, you want to get all the girls on one playthrough. Well, it can be done. It is much easier to get all the girls with one character who starts out rich with full starts but it can be done a fresh character.

The key is to avoid all the girls until you unlock the dream girl Emma. No girl can be your girlfriend unless it is Palla and only Palla. The wiki also mentiones Audrey and Lexi but they can't really be your girlfriends. You have to be very careful with how you handle the office party and make sure Alttea really likes you before that party starts and then make sure you don't go to prison or get fired. You have to unlock Emma and finish he story before the CEO's daughter becomes your pet.

You will need to make a plan for how you are going to deal with not having all the skills. Likely you'll want to only get skills from the dialog that you can't get from learning in game. All girls one a fresh character can be done but there are many opportunities for girls to soft lock when they interact with other girl's story lines. Bree and Sasha can soft lock each other. Shiori and Aletta can soft lock each other. The band girls can soft lock each other. You have to be very careful and know when to roll back. If you make a mistake then you have to start all the way over from the beginning and do all the grind all over again.

Or just give up on this and accept that New Game Plus is the future of this game and we should never go back.

Strategy for getting all girls on one character (fresh or with all skills)
1: Whenever you unlock an new girl find a stopping point in her story where you can prevent it from progressing to girlfriend status.
2: Don't have sex with the girls. Keep it in your pants.
3: Once you unlock Palla focus on her. She alone can be your girlfriend. Ignore Audrey but if you happen to have the threesome with Palla and Audrey it is ok.
4: If you go on a date with a girl, do not have coffee with her. End the date early. One time sex with Bree is ok but only ONE time and that means no sex with Sasha.
5: Get each girl up to a certain point an stop her there while you wait for Emma to unlock.
6: Once Emma is unlocked put all your attention on her and finish her story until she says Palla is ok. After that, do one girl's story at a time until you get all of them.