I think it'll be better if you start with those that are already translate, and play the english one first then the japanese one to get the hang of it. After that, start with the easy non-translated one with a dictionary in hand and slowly make your way up
for first-timers, I think Tokimeki Memorial Girl's Side, (the third one have a psp version) is the best because it's full-voiced, and the heroine doesn't talk that much, plus it's set in daily life, so the language used aren't complicated
Next is Hakuoki because there's an english version, and it'll help serve as your initiation to non-daily life games
Next, more pure daily life games, like Summer Lovers
Brother Conflict is okay, but I think the system is kinda complicated~~
Atelier Alkrone is good also, but because it have alchemy elements in it, it can be kinda confusing......
Aim for the popular ones at first because they have lots of tutorials to help you if you're stuck
Also, makes sure it's fully-voiced!!