My 10 mths old baby just sleep around 10 hours a day. How to increase the no of sleeping hour per day?

Day sleep is quite good so I would work on the night sleep. It sounds counter intuitive but a sleep consultant I went to suggested I put my baby to bed early. So we used to put him down at 7-7.30pm and he started sleeping 11 hours straight at night! The consultant also recommended resisting the need to pick the child up as soon as he woke up if it was too early. So let the child be in his cot if it's early and sometimes he might put himself back to sleep