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A technical background is, naturally, a great help. Technical training inceases your confidence, and knowledge, when passing this on to others.
IMO, with either of the above, one is, still, extremely weak, without the hand on experimentation and experience.
The important thing about user experience is to try and put yourself into the mindset of the expected user of your app, form etc. No point just devising it for someone with your own viewpoint and experience in using the interface. Sometimes you get it wrong but hopefully if there is a feedback channel for your users to respond to, you can then learn for next time!