Sleep training

LO is almost 4 months old and want to start sleep training soon.Over day we usually go :sleep,eat,play.

For bed time we have some kind routine:eat around 8-8:30 pm,play a bit,change diaper,put ointment (we bath him every two-three days should I change that).Then bring him into our room it is dark I rock him to sleep and paci is in mouth.After he is asleep I put him into crib (if I put him while he is drowsy his eyes are wide open).So I leave him in room and after 10-15 minutes he is crying in his sleep so I take him out rock him again and put him into crib and he will be done.But after hour or two he will start crying or make noise to wake himself up so I give him paci and he is out again.So this routine sometimes will take me 45 minutes to hour just depends on him and his mood.I track his naps with huckleberry app.

So any suggestions are more than welcome