We did cc with dd who was 7 mo at the time, so a lot younger than your lo. We had got into a habit of rocking her to sleep before every sleep (day and night), and then again when she woke in the night.
It worked a treat for us I have to say. At first we left her 5 mins before going to see her (but not picking her up), then 10 mins, then 15 etc etc. We were going back in 3 or 4 times at first, but I was surprised how quick she settled - by the end of the week, she wasn't even crying when we put her down at night. We also found that by the end of the week, she knew she was able to get herself back to sleep, so when she woke in the night, she'd cry for a bit, but then settled herself down.
I'm sure it's easier the younger they are, but if you hav a month off, that sounds like a good amount of time. It's not easy at first, as you're so used to comforting them when they cry, but do stick with it.
Also, we read that you have to stick to the same adult each time, ie, if you put ds to bed, it has to be you that goes in after the increasing time periods to see them, and vice versa if it's your partner.
'Solve your childs sleep problems' was the book that we read for advice, if it helps.
Good luck!