Starter VNs

Steins Gate, Danganronpa, Zero Escape.

It's a good start I think.

check this threads
https://www.steamgifts.com/discussion/MfhVf/visual-novels-a-newbie
https://www.steamgifts.com/discussion/MOEEv/best-visual-novel-to-start-with

Everlasting summer - It's free to play on steam and story is quite good.

There are many genres, like there are for books.
Which genre do you enjoy? Horror, science fiction, romance, sad stories?
Are you interested only in visual novels with choices (and different endings) or would you be okay also without choices (kinetic novels)?
Are you interested in dating sims or would you find them boring? Do you like fan service or do you hate it? Is 18+ content okay for you?

Try short kinetic novels first. It's a good choice to see if you're gonna like the genre or not. Eden* and Planetarian are great for starters.

Doki Doki Literature Club.

Don't ask, don't look for spoilers and don't panic.
It's free on steam and it's worth your time.-

Well, if you're a starter check out the Humble;
https://www.humblebundle.com/games/hunie-sekai-bundle

$1 tier for FAULT is definitely worth it. Second and third depends on your interests.

If you can go for DRM-free, try Katawa Shoujo. It's free and one of the best VNs I've read. Other than that, Lucid9 is another free VN that's pretty good, but it's kinetic (no choices).

I've made a guide especially for people in your position! Keep an eye on the tags I've added for genres/aspects that sound appealing to you, click the pictures on the side

The best free VN for you to start with is something probably like Katawa Shoujo - it's the best 'standard' (ie high school romance. So many of them are high school romance) VN I've read. Likeable protagonist, interesting story, routes that are both emotionally intimate and sexually intimate. The protag and his partner make each other better and help each other, and the girls are written like people, not funbag fantasies.

The best VN period is the House in Fata Morgana - gothic horror/suspense, with a labrythine story, incredible mysteries to uncover, gorgeous writing and art, and at its center is one of THE BEST love stories I've ever read.

Hope it helps!

Go! Go! Nippon ... cant really go much more basic then this one :p

Over The Hills And Far Away. One of the best I have read!

Jouka no Monshou - Emblem of the Sacred Flame is pretty good, probably the only VN I've liked so far. Also likely the only one based on the (awesome) movie Equilibrium/Librium/Cubic, so Dystopic Sci-fi and not lovey-dovey stuff. Basically fanfic, but it's good quality art and decent music and writing. It just...ah...tends to crash a lot, so you have to save very frequently.

It's not on Steam, but it's free.

Edit: Changed the link to one with more languages (there's a link to the other one there) and fixed the name. I didn't realize the scenario person (writer?) worked on Fate/Stay Night and Psycho-Pass Sentaku Naki Koufuku and both he and the artist worked on Fate/Grand Order.

Depending on what you want out of a VN, Analogue: A Hate Story would probably be my top recommendation. If you're looking for cutesy romance or a dating sim, you won't find it, but if you're looking for an engrossing plot, amazing worldbuilding, characters with which to empathize, and some of the best music on Steam, I highly recommend it. Here's my review if you want to learn more.