If you have tested on Ancestry, you need to build a tree with as many ancestors as possible. Hopefully then you will get some common ancestor matches and you can use those to help group the rest of the matches.
What I did (not sure if this is the Leeds method) is create groups for each great grandparent pair. E.G. P1GSmithJones, P1GBloggs/Dickens M1GHowardRivers etc. then when you get a common ancestor, add all the shared matches to the same group.
Once you have things grouped, start looking for common surnames within the group and try to build them into a single tree with a common ancestor.
However, having said all that, what cracked it for me was more "social research". I found my grandmother on the 1939 census and the widow she was working for had a son of just the right age...
Good luck!
R.