It's difficult at first visually to grasp a moderately sizable number of objects- like frets, or fret spacings-- with any precision and quick apprehension about how many there are- in fact, without it simply looking like a vague "many" as a number. That human limitation would seem to be the basis for primitive cultures' counting systems which consists of "one, two. three, many", so, the "moderate" alluded to above does not have to be very large. It is, though, pretty easy to distinguish between two and three. So, start out by trying to be aware of the fifth fret not as number five, but as number three beyond two, or the reverse. Build strategies from there- you'll find it works from a capoed or non-capoed perspective. The following works for the fingerboard generally, the capo not applying: One of my teachers once told me that one of his teachers had told him that the seventh fret was the one that, when forming a bar on it, the tip of the first finger looks like its pointed right into your face. Of course, this is predicated upon what are the exactitudes of your sitting position, and the trouble with the advice, according to what my teacher then said to me, is that it always looked to him like there were about forty frets on which the barred first finger appeared to take on that aspect. Nevertheless, I found it to work. And it worked for the seventh fret. Try to find if that's your "bar points you in the face" fret.