Among the ERs in your possession, choose those where you got the lowest votes.
Among these precincts, identify where you are strongest, i.e. where you are sure you have many more supporters who voted for you than the votes the ER says you got.
Collect sworn statements from these supporters, attesting that they are registered in those precincts and that they voted for you, until you have, say, 20-50% more sworn statements than the votes you got. The more the better.
Use these to ask that the votes in the ballot boxes corresponding to these precinct clusters be recounted.
If you find significant discrepancies between the recount results and the machine count, use this to ask that other ballot boxes be opened for a recount.