"Know your connection reliability" is the best advice I'm able to give. When I am on a 3G connection, I place 5 seconds before deadline or 7 seconds before deadline. When I am on speedy wi-fi, I go the whole hog and bid 1 second before deadline.
A strategy that has worked well for me is... bid early in the Initial Round. Make sure you are not the final bidder in the Initial Round. Then go the last second of the First Round. If it goes to a Second Round, be the first to bid, allowing the other bidders to get ahead. Then bid last second in the Third Round, then first in the Fourth Round, so on and so forth.