When a sharp symbol appears after a note, it raises the pitch of that note by a half step (or minor second). When you look at a piano keyboard, a sharp changes the pitch to the adjacent key to the right.
In the keyboard below we see that F sharp is the key immediately to the right of the F key. Notice that F# and Gb are the same piano key – this means that they are enharmonic notes.
Here is what F and F sharp look like as notes on the staff.
Like flats, a sharp may move the pitch to the next white key when two white keys are next to each other on the keyboard. In this case, E sharp is the key immediately to the right of the E key (E sharp happens to be enharmonic to F).
Here is what E and E sharp look like as notes on the staff.