Several features related to selections could save you oodles of time down the road if you add them to your repertoire now.
Saving selections: I never thought saving a selection would be useful until I was working on a more complicated piece and had to select content that was not easily selectable. If you go through the trouble of selecting artwork, you can choose Select > Save Selection and give the selection a name (see Figure 6). Later, you can simply choose the selection name and the artwork will be reselected.
Figure 6 Save a selection
Locking/Hiding content: I wouldn’t know what to do with Illustrator if I couldn’t lock/unlock or hide/show artwork when attempting to select content. You can use lock/unlock to make it so that you cannot select certain artwork. To lock/unlock artwork, you can select the artwork and either choose Object > Lock > Selection or the keyboard shortcut Cmd+2/Ctrl+2. You can use hide/show to temporarily hide content to make a selection or even for versioning. To hide/show artwork, you can select the artwork and either choose Object > Hide > Selection or the keyboard shortcut Cmd+3/Ctrl+3.
Select Similar (Same): This is one of my favorite features in Illustrator when it comes to selection. Suppose you had a lot of artwork in a project with a fill of black, but you wanted it all to have a different fill? By selecting one of the objects with the black fill, you could choose Select > Same > Fill Color (see Figure 7). This selects all artwork with the stroke weight so that you can then make the change.
Figure 7 Selecting artwork by similar properties