How to become a better researcher in a shorter amount of time?
My first, and maybe best, advice would be to do more collaborations. Collaborations with local and remote colleagues. Collaborations with students. Build yourself a circle of people willing to work with you so that you learn from each other. Start with your own advisor and try to get to be a part of their circle.
Go to conferences and use them to expand your circle. Talk to a lot of people. Share a lot of ideas. Take a student or two along when you go to conferences. Introduce them around. Talk about ideas between sessions.
Write a lot of joint papers and be generous about such things as "first" authorship. Work with people who you treat as equals and who treat you the same way. Give a lot of help to students and include them in your circle. Keep the relationship alive after they finish their degrees. Try to assure that they learn everything they need to build a good career.
Build a critical mass so that better work gets done by the ever expanding circle of contributors.
Do this even if you are an introvert at heart, as I am.
The other answers are right about building friendly networks of collaborators, but I think there are caveats to that. Here are the things I wish I had known sooner. Warning: I'm not sure how generally these suggestions will apply or how much they are specific to my own personality flaws.
Collaborations are good, but don't say yes to everything. While others may think that you can contribute to their research, you are best qualified to know how suitable your expertise is for a given problem. Do not try to hammer the methods you know into problems for which they are not well suited. You will spend a lot of time and, in the best case, produce mediocre results. It's okay to say "I'd be happy to collaborate with you, but I don't think I have the right skills to solve this problem. Maybe you should talk to someone who does X." Find the right collaborators who have methods that complement yours and visions that overlap with yours. Then be loyal, helpful, friendly, and prompt with them.
Learn about funding agencies and how funding works early. Talk to your advisors, talk to program officers, and get practice submitting applications as soon as you can. Submit early and get feedback from reviewers. You might learn that a particular solicitation is not a good fit for your research. Even if program officers encourage you to submit, you may find out that the pool of reviewers (for the US, this could be an NIH study section or the usual pool for an NSF program) do not look favorably on your research ideas or methods. Find the reviewers that do.
Be ready to give up on things that don't work. It might not be worth your effort to make something publishable (in a peer-reviewed journal) for a project that isn't working out as you hoped. Hammering away at things that are not working will cause poor motivation and procrastination (and even maybe the temptation to compromise your ethics). Since it's bad science to not publish even partial results, quickly throw your results together and publish on a pre-print server (arXiv or bioRxiv). Move on. Spend your efforts on projects that are working: you will be more motivated and the results will be higher quality.
Manage your time, willpower and brainspace carefully. They are finite. Being an academic researcher (or maybe other kinds too) means you need to be self-motivated. You have to learn your own psychology and find ways to optimize your productivity under the constraints of your compulsions and fatigue. Be aware that most people have a tendency to assume that their future selves will have more time and willpower than their current selves.
Don't be too hard on yourself. You won't succeed in many things you try and you will spend time on a lot of things that go nowhere. You are trying to do things no one has done before, so a lot of failure is be expected. Just keeping moving on.
If you are introverted, or traveling to conferences can be expensive or out of reach for you:
You should read and read as much as possible articles and published manuscripts. That is the only way. Plus seminars.