As mentioned, very frequent daytime naps and daytime feeds will help most.
Try limiting awake time to 60-90 minutes in the daytime. That may mean sleep time starts after 40 minutes awake, allowing for 20 minutes relentless movement and sucking to to get baby to sleep (depending how exhausted baby is how long it takes to get baby to sleep).
2-3 naps of 30 minutes is nowhere near enough.
With 90m awake time and 30m naps, that would mean
7am wake, feed, awake time
8.30-9 nap
9am wake, feed, awake time
10.30-11 nap
11am wake, feed, awake time
12.30-1 nap
1pm wake, feed, awake time
2.30-3 nap
3pm wake, feed, awake time
4.30-5 nap
5pm wake, feed, awake time
6.30-7 nap
7pm wake, play, bedtime routine
8.30-9 bedtime
I am not suggesting you obsessive clock watch, but just to give an idea. That is 5 or 6 naps of 30 mins, assuming a 7am daytime.
A dummy and naps in a bouncy chair helps with daytime naps.