Possibly the best thing you can do to improve your skills as a designer is to trust the process. That's what sets an experienced designer apart from the so called amateur. If you are just starting off, chances are that where you see a dead end, a better designer just sees a bend in the vision. The only difference is that they trust that if the right questions are being asked, they can steer the ship back on track. Much like anything else, the only way to trust something is to see it more.
Breakdown of the experienced designer
I'm talking about the 'seen it all, done it all' category of designers. The ones that have stories to pull knowledge from, but more importantly, have the confidence to keep going when frustration kicks in. They don't boggle their minds down with a bezier curve that doesn't work, or the letters that just aren't kerning properly. They set a big picture. The problem they want to solve. Keep that consistent and they know exactly why they are doing the frustrating things.
Practice the process
Absorb the feeling of being in that rut. That moment when you are staring at a pile of colourful post-its on the wall and your mind just went blank. Or the question that your friend just asked that totally threw you off and probably makes half your arguments invalid. These are all small obstacles and if you fold too early, you're the only one that can call yourself a fool.
It truly is scary to always position yourself to be tested, but know that every time you do that, you are getting better. It's fun to do the things that we are good at because it gives us the confidence and strokes our ego a lot, but the only way to grow is to try the harder parts. Professional violinists go through this process on a daily basis. They practice a ton, but they only focus on playing the hardest parts of the music. The parts where everything can possibly go wrong. That's how you get 'better'.
Drink the kool-aid
If you truly believe that everything has a way of working out, bring that positivity into your brainstorming. If you have people around you that aren't scared to shut you down, you have taken a good first step. Now, there has to be someone that will believe in you at all the times - you. Cue the corny dialogue. Trusting the design process has a prerequisite of trusting yourself. Not as a designer, but a capable human being that wants to solve a problem.