I try to learn by myself so long as I'm not influenced by previously watched videos, which is sadly more often than not just on the basis of watching reviews play and finish games before I ever do, or otherwise I end up buying those games because of them and then play them influenced by their reviews.

Depends on the game, most of the time I use external sources only if I need to know which mob drops item xyz.

Some other games I use walkthroughs for, either if I already played through it and want to rush through a second playthrough or the translation is so bad I need a pointer of where to go next.

Sometimes I just get stuck and need to look at a walkthrough, but I think this is something most do.

Ideally the game should introduce you the ropes as you play. Tutorials should integrate playing. To complete the deal, good tooltips, relevant hints, an accessible help system or enciclopaedia... Not reading long manuals anymore, it feels too much like work nowadays. There are exceptions, but the game really really has to be worth it.

Added: If the manual is well written and enjoable to read, that is a big plus.

To all participants in the thread:

Perhaps this is too formal or even unnecessary but, thank you for taking the time to respond.

Back to the topic, it is tempting to generalize the answers to mean that most average game enjoyers prefer a more interactive experience (except Chilean comedians). The problems with that assessment are the tiny sample size and the answers are all from a subset (forum participants) of a subset (forum readers) of another subset (GOG members) and any conclusions may or may not apply to anyone else. Still, some information is better than none. Mostly.