What can I do to get my baby on a more regular sleep schedule?

Set a pattern. I find it helpful to push baby into "circuit training". As baby wakens/feed first; then change diaper & bathe as needed; play with baby until tired:then back to crib for 2 hrs before starting over. At night mn+ baby gets you up for feed(hope 4-5 hr sleep) but days push a feed after 2hrs rest. Your goal is to never let baby deep sleep during the day (3+hr) and to harness all sleep energy for feeds.
Come to office.... And find out. It's a little tease but too much info to pass onto in this short space.