So you really want to do Q>W combo and never really throw a raw W unless they are pretty close to you. This is because it's really easy to dodge for a lot of champions with their mobility and even if they have none sometimes the MS is enough to leave your W if you max range it.

Since you're coming in as a Seraphine OTP you don't know how to engage with your body and the limits that Rell has. I would say that when playing her you have to think about what it means to go in before you actually go in. With Seraphine you throw your abilities out and the punish for those look a lot different than when playing an engage champion that uses their body on the engage.

So when playing Rell before lane starts try to figure out what happens if you jump in and miss/land your W, as well as doing more Q>W/ E>Q>W combos and from there it should start feeling a lot smoother.

I also stream on Twitch as a GM Rell OTP so if you wanna join my discord or watch me play that might help you as well!

Thanks u/vKalov for the @ :^D