The problem is, I can now read Welsh (either silently or aloud) and get the gist of it, but it's too hard to do it for pleasure and if I consider it as Welsh study, ploughing on and ignoring all the words I don't understand is not going to expand my vocabulary. However, looking up every unknown word as I come to it just makes the whole process frustrating and boring. I know because I've tried that before.
So, this time I'm experimenting with a compromise. As I read I'm writing down a) words I don't know and b) phrases I understand but feel might be useful to learn by heart (mostly idioms), but I'm not looking up the meaning (unless it's vital for understanding). I'm writing the unknown words in a physical notebook, along with page and line number so I can easily find the them again to see the context.
My plan is that when I've finished the book I'll spend some study time going through the words and translating them and perhaps making flash cards to learn them thoroughly. So far it seems to be a reasonable compromise and it's enabling me to make steady progress.