How can I negotiate for a higher pay?

Your current salary should not be a presedence of your next job salary.

my wife changed job recently and managed to negotiate for a 50% increment.

UX designer is very high in demand so you should try attending a couple more interviews to secure a few more offers on hand for comparison.

if you feel that the company is trying to "lowball" you, you're already off to a bad relationship with this potential employer.

instead of giving a range, give a firm amount(of course it must be justifiable), if they negotiate down, you can be the one who question them why They are not matching your expectation.

Hi Anon! You can check out payscale for 1). Also, if you have friends in such roles, it's good to get a feel from them. But there will definitely be pay variations depending on the type of company (small vs big) and industry you apply for.

For 2) it's not necessary to declare your last drawn salary. However, I think you can ask questions like "How much is this role worth?" during the interview stages to get a good vibe. I think nothing wrong with being honest about your last drawn if they create a safe space (meaning you feel like they are not going to use it as a benchmark) and you can share with them why it was low.

For 3), it really depends. HRs are given a hiring budget yearly so it's natural for them to try to keep the cost low. That's where negotiation and prior research come in - where you know your own minimum salary which you'd personally settle for. Also, communicate clearly what is your value proposition. If you can show them how you would value-add to the company, I reckon any company with fair hiring practices should give you your dollar's worth :)