Let's take a look at this chart. 
This chart shows you all the flats & all the sharps.
Let's look at the middle.  This is C.  Key of C has no sharps nor flats.
The key of G is at 1 o'clock position & it has 1 sharp
F#.  For D there are 2 sharps. You add the C#.
For key of A-  it is F#, C# and G#
so you just add an extra # to the previous one
Key of E:  F# C# G# and D#.  For B, you add the A# in.
For F#, you add the E# there. And C#,  you add the B#.
So it is F C G D A E B.  Circle of 5ths  in this order
F C G D A E B - going clockwise putting the C
at the 12 o clock position.  For the flats,
you add it in this order: B E A D G C F
For Key of F - it is Bb so you can begin in the reverse order
B E A D G C F  for the circle of 5ths.  F has one flat - Bb
Bb has 2 flats - so it is B and E
so it's Bb & Eb.  Eb has three flats
so you ad the Ab.  so it's Bb Eb Ab.  For the Ab key there four flats.
B E A D. You look at the circle - B E A D -always  go in this order
Db -  Bb Eb Ab Db Gb.  For the Gb  you add
in the Cb, and finally for the Cb, you add in the Fb
So altogether there are 1 2 3 4 5 6 7 flats.
And for the sharps: F C G D A E B
 you go in this order.  F C G D A E B
So there are 7 sharps: F# C# G# D# A# E# and B#
