My first really big challenge years ago was applying poly to give me a smooth even look. When light reflects on a piece, we want it to look consistent without drag. Drag is when the poly dries before you come back over for the next strip of poly and you see stripes because you "dragged over" the poly when it had already started to dry.
It took me about 2 weeks to figure it out after searching for the answer and then it was smooth sailing from that point on. That two weeks I went to sleep thinking about it and woke up thinking about it. I'm like that. I HAVE to figure it out.
I now use a damp sponge or sponge brush to apply and use a product that is easy to work with. I now carry it in my online store, Furniture Flipping Market. I use Water-based Polyurethane by Retique It. Once you get your technique down, your frustration is over and you can go on to the next challenge.
I encountered my next poly challenge just a few days ago. You'd think someone who's been doing this for ages would have it all sorted out by now, but honestly, the more you do, the more you find out what you don't know or experience something you haven't run into yet due to a change in circumstances or product.
It's how we progress and get better. Try new things, new challenges, experiment and try to solve even the smallest issues. Then I pass it along to my members on FFB and occasionally here on LMDH for you to see.
Here is my video explaining what I did just after I discovered it worked well and gave me the result I was looking for: