Just can't play well as Janna
Hi guys I am a silver 4 player, just trying to work out how to play Janna. I've played quite a few games with her, I've read all the guides, watched commentary videos, analysed many pro matches with Janna players etc. but I just can't do well when I play her. I always end up feeding, always miss my shield by 0.1 second after they poke my adc, always miss the knockup when I try to cancel a dash etc. I am just not able to play this champ both mechanically and strategically and she is really fun and it really frustrates me. Are there any tips that you guys have for me? I have like 27% winrate on Janna.
By contrast when I play Sona(my other support), everything goes perfect, I find that I have all my spells when I need them, my ults are on point, adc's butt is always saved by me. My winrate is 77% with her. I mean she is of course a lot easier to play but still, both squishy ranged supports and there's a huge difference in my effectiveness between the two.
Also any general support tips would be greatly appreciated.
best support item to get

and
+
(very cost efficient).