How to win a bid when seller has multiple offers????

First of all, its hard to find a real good deal on MLS nowadays and when you find one, there are always multiple offers. For a typical investment property under $100K, I usually use the following strategies -

-Go very aggressive on Earnest Money, up to 25% of the listed price. I recently managed to acquire a property for my client for $525K which is valued around $550K+. We put $50K as EM  and I believe it helped us win the bid. During the informal conversation after closing, the Listing Agent indirectly told me at that I got that deal not because it was 'the highest offer' but it was 'the best offer'. I've done the same for investment properties under $100K (put $5K-$20K as EM).

- Cash Offer: I believe it is kind of pre-requirement for a typical investment/foreclosed property and most of the investors do this so I don't think this helps much, especially under $100K properties. 

- Go aggressive on closing date: Not sure if this really helps, especially for foreclosed/REOs

I will appreciate thoughts from experienced investors and wholesalers about how they use these and/or other strategies to win the bid where seller has multiple offers.

thanks,