Trying to remember the notes in every Key can be challenging, especially where Sharps or flats are involved. Here's a method that may help some who are struggling in part while having general knowledge and understanding of the Diatonic scale.
Note; Each Diatonic scale contains one Tritone in it's make-up. the Tritone is located dead center between a Note and it's Octive. Example; Starting from
A to A (Octive) would take 12 half steps to complete, so the center would be at the 6th half step interval from A.
Starting again from A to A (Octive) would also take 6 Whole steps to complete, so the center would be at the 3rd Whole step interval from A.

In half steps from A is; A-A#-B-C-C#-D-D#; So from A, D# (Eb) is the tritone.

In Whole steps from A is; A-B-C#-D#; again D# (Eb)

So, 3 Whole steps (W-W-W) from any note is it's Tritone Interval.

With that said, this method uses the Tritone in Diatonic scales as reference points.
Since we used A to figure the intervals, Let's use the A Major scale and find the Tritone. A-B-C#-D-E-F#-G#. The only notes that allow 3 whole steps and remain in the scale are D and G#. So the intervals of the Major scale that contain the Tritone are between the 4th (D) and 7th (G#) intervals.
Finally we come to the Tritone Method.
With sharps, the method involves looking at the last Accidental in a key, so in the Key of A above, it's G#, a half step below A. Now if we sharpen the other note of the tritone (D) to D#, it becomes a half step below E (the same distance G# is from A) (the Tonic) So, if we start from E and follow the notes of the A Major scale and add our new sharp, it's E-F#-G#-A-B-C#-D# and the E Major scale. If we did the method again, D# and A = Tritone, sharpen A to A# = the B Major scale.

Now with flats the method involves looking at the last Natural in a key; Bb Major scale Bb-C-D-Eb-F-G-A. You see it right? 4th and 7th swapped roles. Last Natural is A. W-W-W = Eb (Tritone) Flatten A to Ab and the only note a half step below relating with the Tritone is D to Eb.
SO, Eb-F-G-Ab-Bb-C-D = the Eb Major Scale.
Now, say you were to play a Bb7 chord in a progression (Bb-D-F-Ab). Notice how the 3rd (D) and the b7th (Ab) are the Tritone in the Eb Major scale. By flattening part of the Tritone in Bb (A to Ab) automatically connects with the note a half step lower (Eb to D) in the new scale to form a Tritone. Ab now becomes a Perfect Interval to Eb.

Next .....Ab-Bb-C-Db-Eb-F-G = Ab Major scale

With Natural minor scales, the Tritone is between the 2nd and 6th intervals.