No products are associated with this question.
As usual it is a good idea to look in Matlab's FileExchange before asking in the forum. Standard problems have been solved by others before most likely:
Copy subplot.m and edit line 128 (or there abouts)
inset = [.02, .018, .004, .01]; % [left bottom right top]
to be values more to your liking. Either save the new file as subplot.m (which will affect all subplots) or something new (e.g., tightsubplot) and use that when you want tight subplots.