Add a note to blocks in your code to let you and others know what you were doing. Comments can be added by right clicking on a block and selecting the Add a Comment option. Your comment will now be saved and can be accessed by clicking on the question mark at the top right of the block.
Condensing blocks
Click a button on a group of blocks to condense them and allow you to have more space available on your screen. Condensing can be done by right clicking and selecting the Collapse Blocks option.
Typeblocking
Know the name of the block you need? Click on the screen and start typing it's name in. This should cause a list of blocks with the matching titles to the typed word to appear. For more help on this trick, check out the typeblocking page.
Fast deletion
Instead of dragging your block or blocks to the trashcan in the lower left corner, just select them by clicking your mouse and hit the delete key.
Copy-pasting
If there are certain blocks you will need again, just copy and paste the blocks.