If you are talking about Japanese Acer, then cuttings from them strike at a very low rate and can be tricky. Some people claim success such as the link below.

http://www.gardenadvice.co.uk/howto/gardenplants/cuttings_softwood/index.html

A pal of mine struck a snakebark maple cutting and it barely survived for three years only producing two leaves at the tip each year. Now after finally taken, it has grown to nearly five feet tall in three years and looks very attractive.

If your Acer produces seed, try sowing it fresh....I have had some success this way. Obviously, they take some time to grow though.