Hi K.,
A 10 month old should get a total of 14 hours a sleep a day, including naps. I have worked with toddlers for about 17 years, and I have found over the years that children move to 1 nap between 12 & 15 months old, normally moving the morning nap to about 11 am and sleeping about 2 hours. By 2 year old the nap is at 1 pm and still is about 2 hours.
I suggest trying to lay your baby down for an afternoon nap 15-20 minutes earlier, but keep trying that afternoon nap. He should keep 2 naps a day for a few more months, but as he ages, you will need to adjust the time.
During a normal, your child should lay down easliy with maybe a little fussing, but fall asleep soon. If you see fussing for a while, as I mentioned, lay him down early until you find the best time. Your child's sleep schedule will change often in the next year or so. I recommend to parents to watch for the over tired signs you're seeing now and alter the schedule.
Good Luck
R. Magby