I think we can all feel a sense of imposter syndrome, and that inner voice saying you are not capable. You are ! I think we all need to recognise that work can be challenging and not always as straightforward as you want it to be, which is where the doubt can set it. Its all about building that resilience for me, don't give up. If you want something just keep working towards it, even if that means taking it slowly.

Keep your mind and eyes open as there are are so many opportunities

In terms of applications, it sounds obvious, but make sure you read the job advert thoroughly, and tailor your application to evidence your experience of the key things the vacancy-holder is looking for. i've reviewed hundreds of job applications which often fail to do this. In terms of doing your job, be clear on your responsibility and then commit to delivering it with energy. Focus on the most important things that need to be delivered, structure your time well to achieve these, and be sure to consider others as you deliver - hitting a target is great, but not as great if everyone else's delivery has been negatively affected by the way you've worked and interacted - remember to keep the big picture in mind. If you are considering whether to move roles or take on additional/new responsibilities, my advice would be to go for it. It's often easier to stick with what you know, and to find reasons not to try new things - "maybe next month, or next time". In my experience, trying new challenges always builds your experience, resilience and understanding, and as long as you don't change roles really frequently, you will rewarded in your career as a result of taking the plunge.