X2 on Practice makes Perfect.

I prefer and always use a penetrating oil based stain.

I never use conditioners.

top coat with satin polyurethane.

Is this on new wood or does it have a finish on. It

https://www.homedepot.com/p/Varathane-1-qt-Black-Classic-Wood-Interior-Stain-349558/308350340

I’d try something like this.

Thank you!!

It’s on old wood that was never finished. I plan on sanding it twice; starting with 100 grit and finishing with 200. After that I’ll start with the black stain and then finish with satin polyurethane as you recommended

You may want to consider finishing some sample material as WoW was alluding to. Staining can be tricky if you haven't done much, and the difficulty level on windows is about as tough as it gets. Lots of ins and outs, taping, etc.

Any pics of how it came out?? Thank you.