We got help from a sleep specialist and we haven't had any problems since he was 16wks old. She spent like 3hrs with us, looked at his room and mafe suggestions then wrote a program for us. We were so sceptical as he was prem and had colic but sure enough within a couple of days he was napping during the day and sleeping through the night and all we had to say was the magic phrase. She used the E-A-S-Y routine if you're just looking for routine and not the sleep training techniques, can probably google it.
And just so people don't freak I didn't start doing this until like 8-10 months or so I don't remember the exact time. It was 5 years ago. My son is now 6 and ever since then he's super easy to get to sleep once he could walk all I'd have to say is its bed time and he'd walk to his bed.
I taught my son to self sooth. I would put him in his crib for bed time and he'd cry for about 10-15 minutes I never let him cry longer than that. Then I'd go in and calm him down by talking to him and letting him know he's not alone then I'd walk out again. And I'd do this until he was so worn out from crying he'd fall asleep on his own. It was really hard for about 2 weeks I had to do this and it sucked because you want to give in but I never did and after that once it was bed time he'd just lay awake for a bit until he fell asleep on his own and he was okay with it because he knew what he had to do which also let him sleep through most of the night only would wake up maybe once sometimes