Twenty minutes a day on anything turns into a real skill by the time your friends notice.

Small daily amounts look insignificant while they are happening, which is why almost nobody sustains them, and they accumulate at a rate nothing about the day reveals. Twenty minutes is roughly two full days over a year. The growth is invisible to you as well, since you only ever compare against yesterday. Then at some point other people start commenting.

Pick one thing and attach it to something you already do daily, after dinner or before the bus. Keep the amount small enough that a bad day cannot break it. Do not measure for three months, then compare against where you were rather than against anyone else.