I tried playing by myself for the most part, but I sometimes used a walkthrough when I failed to get on a route too often.
I remember Kyou route being the hardest to complete and I’m not sure whether I used the walkthrough for it or just brute-forced my way through it by trying all options. I probably used it for Misae route, too. I believe I used it to get on Kappei route. And then there’s stuff like Koumura route and Jet Saito that are nearly impossible to get without a walkthrough.
Overall, I actually like the amount of possible choices in Clannad, because it actually feels like a game that way. The difficulty of Kyou’s route, for example, added to the overall experience of the route by showing just how complicated and hard the situation is that the characters have to face.
Though it does get frustrating if you fail to get on a route several times. And some decisions are not at all intuitive, like in Misae’s route where you basically have to tell her the exact same stuff as some other guy from her past.
What I also like about the choices is that you are sometimes on a fork between several routes and Tomoya has to conciously decide which girl he’ll keep pursuing ans which one he’ll stop visiting.