There is no way to see the highest offer. That is private information between the seller and the customer.
There is also no way to see if there are offers or enquiries being made.
Are you talking about bids on an Auction?
Bid.
Bid once, bid your maximum. Don't forget to check the shipping cost and delivery time.
When you have made a bid, no other person can make an offer and any Buy It Now disappears.
Most members will add "bid late" but while you dither the seller may accept another offer.
If the item is Fixed Price, make an offer, but if you are refused, just buy it.