1. Do the dishes or a chore that your significant other hates doing.
Find out whatever it is that they hate doing the most and do it for them. Even if it's just a one time thing, it'll mean the world that you've listened and remembered.
2. Pick up the phone and give them a call instead of texting them.
Have a long drive? Or a funny story about something that just happened to you? Pick up the phone and give your partner a ring.
In this day and age, they may be confused that you opted out of texting to actually talk, but they'll find it romantic when you explain that you just wanted to hear their voice.