Recognizing and acknowledging important dates:
Get a calendar, or set up your phone or tablet or whatever. Mark important dates. Set it up so that you get an email or a text reminder. If you're really bad at following through (some people are, not beating on you here) -- set up a series of reminders -- one week ahead, three days ahead, day before.
Acknowledging: Write a note, get a card, buy a little gift, flowers, whatever...saying something like, I know this must be a really hard day for you. I'm so sorry I hurt you. I love you. (try to write something at least a little different each time)
My FWH was terrible at this. He said, well, if I do all that with a calendar, it's not sincere and authentic and spontaneous. My response, what I want is *recognition*. What I want is *effort*.
You know what the dates are -- look at your timeline.
It's also nice to do these things "just because". Send a text, stick a note in your BS's lunch bag or briefcase...
Send her the link to her favorite song on youtube.
Do a chore that she really hates without being asked and without pointing out that you did it. Even better if it's a chore you hate too. I'd forgive a lot if someone mopped my kitchen floor every Saturday morning. Seriously -- put it in your calendar to do it.
Put in your calendar at least once a week: send note, text, or song to my BS today.