Start from a size you already know
The reference on every Howbigle round is an adult human 5 ft 7 in (1.70 m) tall. If the object feels a little taller than a person, try 8 or 10 feet before you fine-tune. If it feels like a room, a house, or a city block, jump by tens or hundreds, then slow down.
Think in multiples, not in pixels
Scoring cares about the ratio between your guess and the true size. Doubling and halving cost the same. A useful habit is to ask “is this about ten people long, or a hundred?” rather than nudging the silhouette a few pixels at a time from a 1:1 start.
Watch the dimension being asked
A bald eagle is scored on wingspan, a blue whale on length, a canyon on depth, a tower on height. The prompt always names the dimension. Matching the right measurement matters more than making the drawing look dramatic.