Sims virtual dating
Bionic Heart was perhaps the most complex visual novel I've made so far (and the only one to be featured in some popular Japanese websites).
I did everything with a spreadsheet program but there are also other useful "mind-mapping" programs including Free Mind.
Usually the endings all feature a beautiful art moment but you can also use it for other particularly important points of the story.
The visual novel Bionic Heart (2009, Mac, Win, Linux) by Winter Wolves is set in 2099 London and offers "bionic beings, complex technologies, relationships and romance." It is fully voiced and has 24 different endings.
When people ask me for advice, I always tell them there is not a single, universal, valid answer.
There are several ways to sell your VN or dating sim (or games in general) and I know people who are successfully making a living using very different methods. ~ Freeware The basic idea here is first to gain popularity and a following through a few decent free VNs or dating sims and then try to sell new games to your fans.
To be clear, they originated in Japan and, while many visual novels or dating sims are erotic (or at least sexy) in nature, it's not true that all dating sims have erotic content.
It's really a shame that people automatically label these games as "adult only" because, in many cases, is not true.