It has been a looooooooooooooooong time since I did a SnTT but I found it fitting for this week. The tip is short and very straight forward but will make it easier and more productive for you to work in Domino Designer on Eclipse (DDE).
If you are like me like the navigator in DDE is on the left, and the outline/controls/data views are on the right. You realize that you do not have much space left for code in the center editor. Bummer! :-( To help remedy that you may either minimize or close the views on the right but that really isn't ideal as it takes time and some times you need the views e.g. for XPages work. As an alternative you could figure out which views you use for what tasks and create custom perspectives in DDE for those tasks which isn't for the Eclipse-superuser. You could also choose the easy solution - simply maximize the editor.
Maximizing the editor is easy. You simply double-click the tab or press Ctrl-M to make the editor go fullscreen. When done you simply double-click the tab again or press Ctrl-M to return it to being "in the middle". Easy and quick.
Hope it works as nicely for you as it does for me.