This month's update refines the selection system and adds a new sort feature. The two changes work together to make it a lot easier to group together the pieces you're looking for.
First, when you enter select mode (by pressing the button with a arrow drawing a box) you can now press on individual pieces to select or deselect them. This is in addition to being able to draw a box around a group of pieces to select them all. Being able to select individual pieces makes it easy to, for example, select all the pieces that appear to be part of a particular object.
Next, a new sorting option has been added, called Spread. This takes all of the pieces (or if you've selected pieces, then it just takes those) and arranges them neatly in a circle. One use for this is to layout all of the pieces at the start of a puzzle, so that none are overlapping.
These two new features can be used together to make it easy to sort together the pieces you want to work with. Enter selection mode and click on all the pieces you want, for example each piece that is part of a certain object. Then use the Spread option to arrange all of those selected pieces together in a neat group, at the place on the table where you'd like to work with them.
Finally, another recent change requires that a player in an open puzzle connect several pieces together before they will be allowed to place pieces in their final position on the mat. This is to prevent 'trolls' from going into an open puzzle, taking large groups of connected pieces that players are working on, and placing them permanently in position on the mat -- which makes it much harder for the players to continue working on those sections. Now players who are new to an open puzzle will need to put some work in before they can place pieces in their final position, work that trolls usually don't have the patience for.
Fun facts: over 900,000 puzzles have been completed in Puzzle Together, and over 347,000,000 pieces have been connected... so far!