Focussing on being a better UI designer is not the way to start.

Be a better problem solver first (more so a UX Designer). You should not just start working on being a better UI designer without knowing what context your work will exist in. Specialize in UI later.

A quick overview on how to be a better UX designer
- Figure out and write down in minimum words the goals and reasons for undertaking the exercise

- Figure out the main types of users you are designing for (don't try to design for everyone). Find out what relevant mental model they already have.

- Break down the problem via concept maps (involve others to brainstorm).

- Sketch several solution hypothesis using flow diagrams (boxes containing major concepts connected to each other) (involve others to brainstorm).

- Compare these flow diagrams and identify the best hypothesis to develop and test first. (Failure is okay)

- Now do UI design for each aspect of the selected flow diagram (as you will know how each page/area in the flow diagram works with the entire picture, you'll know what to show the user when.)

- Do not try to complicate your test by adding features/distractions that are not extremely crucial.

- Put in some love and care. Ideas that spawned from your brain have the possibility of giving so many others so much joy.

(Hint* For a lot of products it is about making MOST users get engaged for the LONGEST period. For many others it is about solving a user problem in the Simplest+Quickest+Most-Painless+Most-Joyful way possible.)

A bit more on how to be a better UI designer

- Go back to the basics and learn how humans sense, how the brain perceives, and what makes us get ideas, form opinions and take action. This is a big part of what UX and UI design is about (this is useful to understand and remember too - http://en.wikipedia.org/wiki/Gestalt_psychology#Properties)

- It is also about having a two way conversation between an interface and a human. Follow protocols of a decent and efficient conversation. Empathize. Introduce if you haven't met before. Maintain a flow. Be focussed on the goal. Don't distract and value their time. Be terse. Don't disrespect.

- Know that content is always more important than the user interface. Strive for harmony between what you have to say with how you are saying it with the best UI for that purpose). Use the help of a copy editor or a technical writer. Ensure they don't write more than is needed.

- Learn about the medium and context you are designing for (e.g. how users use computers, web etc)

- Learn about the existing UI patterns that you can leverage

- Browse a lot. Note down what you like, store it as a pattern in your head. Note what irritates you and think about how it could be done better for more users.

- Practice. A Lot.

- Get hold of a good designer and sit next to them. See them work. See how they make their life faster and easier while designing. Optimize your workspace continuously. Look out for new tools that can help your workflow.

- Generating consensus around the flow and UI solution is your job. Get the stakeholders to see the way you think.

-Don't use Colors initially, they derail conversations quickly as humans are prone to judging colors instinctively. Use grayscale and rough way of doing stuff first. Finalize (visual design) after that.

- Ensure that the colors did not change the flow of user's attention on a page.

-Figure out if the flow of user's attention on a page is the way you intend

- Grab five people, give then some basic context and do RITE (http://en.wikipedia.org/wiki/RITE_Method ). Don't listen to all feedback. Designers usually give feedback based on heuristics. Try to get more designers to give you feedback.

- Use web based tools as often as you can. It is easy to share your work and get feedback quickly. There are tools for getting feedback online. But have a meeting at least once initially to explain the context and thinking behind your design decisions.