Well, when faced with the same thing at this age, she was even not falling asleep when pushed in pram for ages, my HV advised "teaching" her. So, I'd feed her, then carry her upstairs wide awake, into cot, curtains closed, and leave her. On HV's advice, she said to turn monitor receiver off (I turned it away) and go somewhere you can't hear screams, turn music on and do something else (I washed dishes in kitchen, felt a blessing to get the time to). After 20 mins, if not asleep, I got her up and went on with the day. Do this at 10am and 2pm (ish, whatever suits, realised my dd preferred 9.30am and 12.30). If she didn't sleep, 2x20 mins break helped me...
1st day, she didn't sleep in morning. By afternoon she was utterly whacked. So after 1st attempt at afternoon nap, I brought her back down, fed her again (she dozed off), took her back upstairs awake, put her down, repeat! On 3rd attempt, she fell asleep after 10 mins! For 20 mins! I kept going, each day, and from then on, she started to drop off more easily. By a week, she went to bed happy and fell asleep. Honestly, if felt like magic. I didn't regret doing it, as she spent less time crying overall, being not overtired, and I could catch up on stuff/have some rest.