Interesting start!
Most important thing in a game for me is player choice, so it's nice to see you can always refuse to do lewd acts with the girls here. Personally the more weight the choices have the more I enjoy them, but there's nothing wrong if they are lighter. I think the sweet point is somewhere between "I refused to have sex with this girl once, so now I'm locked out of her path forever" and "I've not given this girl the time of day once yet she still keeps giving me sweet eyes". If there's a girl I don't care for or outright annoys me the option to tell her off once and for all is appreciated, but being locked out of seeing more of someone I find interesting because I didn't do a perfect run is what I find more regrettable, so on player choice implementation, I think you've erred on the right side of the fence.
Another thing I liked a lot is the male best friend. When the MC is the only male and every other male is either ugly, or a bastard, or an ugly bastard, that feels shallow to me. Like the dev is an insecure person, and he sketchs a world where MC gets the girls by virtue of being the only decent acting/looking guy, cause he can't imagine how he'd get them if he had to exist alongsise other males who are not horribly flawed. We all play these games for the girls; but at least I appreciate when there's a good bromance going. Not only it enchances the experience, but it kinda shows the author has his own vision, and isn't just doing what he thinks the players will like.
If I could give you only one advice, or if you want to only heed one of the advices I'll give you, is that you should make the game you yourself would like to play. Include the stuff you would like to see, be it H-scenes, jokes, plot elements, etc. If you yourself like it and feel confident in what you create, someone else out there will like it as much as you, for sure.
Now, I've seen the topic of sharing be mentioned below. If you want to include sharing, include it. More variety is always better. If you are pressed for time, and have a lot of content you would like to put in, and not all of it can make the cut, maybe don't do the sharing scenes. But I feel just one sharing scene would a lot more value than a tenth blowjob scene, or a seventh cowgirl one, or a fifth paizuri one.
Personally, I'm not as big a fan of "doing the same girl at the same time with my bro" as "letting my bro have x girl all for himself." So how I'd like to see sharing implement would be more like, not-sharing, but stepping aside to let the bro have the girl, or push the girl towards the bro. Kinda like self-inflicted, voluntary cuckoldry. Only my personal preference tho.