Autofill & Flash Fill

Repeatedly entering data and formulas into Excel can become very repetitive and monotonous at times. Using Microsoft's Autofill feature allows one to add formulas and sequential datas through dragging your mouse.

When entering a series of data such as the example provided below, 

you can utilize the fill handle on the bottom right hand corner of the highlighted cell, and pull down to where you would like to continue the series. 

First select at least two cells whose trend you’d like to continue and then pull down on the handle to where you would like to enter the data:

If you’re entering data in some kind of table and there are values to the left or right that go down to the bottom of the table or to where you’d like to stop entering data, you can just double click the handle and Excel will Flash Fill your data up to that row or column: