Retailers use online auctions to sell lots of items. Bidders can learn and pick the best bidding strategy by participating in many auctions. This study looked at bidding strategies in sequential online auctions and found that bidders change their strategies based on their demand, experience, and auction design. Bidders with one item prefer early bidding, while those with more items prefer late bidding. Auction design also influences bidding strategies. As bidders gain experience, they tend to switch to late bidding. These findings can help auctioneers design better auction sequences.