If doing a New run, I suggest ignoring Sam until you see the second dream. After the wedding, get her to 60 lp to trigger Emma's meeting then lower her Lp below 60 (butt slap or calling her when she's asleep should do it). As you wait for the dream and ignore Sam/take it slow with her, just make sure you don't ask any girl to be your girlfriend and stop progressing with girls that want you as a boyfriend (I think Sasha does that on the second date, for example).
As long as you didn't progress with Sam beyond her after wedding complaining, you shouldn't be her boyfriend when you meet Emma and as you probably want to focus on Emma afterwards, it's easy to not progress with anybody else until you get down to business.
While searching for the lucky clover, you can grind stats, job and money. Should you want the NG to focus on Emma, I suggest to pick small penis as your bad trait.
If doing NG+, you should already have max stats, whole lot of money and some extra traits. Just do your things and remember to search for that clover daily (every morning at the park). After you meet Sam, you can try to speed-run her to meet Emma right after. Since a new harem has been added but not all variables might be implemented, I suggest to still just focus on Emma and only try doing the Harem after both have the right/high stats.
Reminder you need to go to sleep while feeling lucky (eating clover) and having high Fun stat (I think 11 or above?) for the second dream at least 10/11 days after game starts