My strategy is usually successful (minus this year):
I have a running list on my phone of gift ideas. Starting in January, it’ll be blank.
All year long, I listen for when she says things like, “Oh, this would be good to have,” or “I could really use one of these, but that’s too expensive.” - we’ve been married long enough that I can tell when she’s just mindlessly thinking out loud versus seriously wishing she had something.
It goes on the list. Little things, big things, cheap, expensive, it all goes on the list.
Around about September, I start looking online, thinking about what shops might have this or that locally, and then, between Labor Day and Halloween, I do the majority of my shopping for her.
This year, I must’ve failed to pay attention, because I have very little on her list and I’m stuck. I have the same issue buying her clothes, as far as fit goes, especially right now, as I don’t think she’s finished losing weight, and she has no particular fondness of jewelry (thank god!) and I refuse to give her a gift card, as I see that as a real failure to know your partner, though this year, she might get a small one for some clothes that she can go and pick out.