Short of being a lesson in kerning, here's a little tip in making your typography look just a little bit better.
Whenever you sit down to design, you should be sure to make the details count. The difference between an amateur and the professional is subtlety. Specifically when it comes to type, it's a good idea to take an extra couple of minutes to refine some of the nuances.
Two of a kind
Let's refresh. According to The Complete Manual of Typography, kerning is the act of adjusting the space between two characters to compensate for their relative shapes. However, because of the particular shapes of some letters, most typefaces have specific relationships between certain letters called kerning pairs.
Software programs do a decent job of approximating good kerning, but you should still make it a habit to go in and tweak, especially when your type gets significantly larger than body copy. Sidestepping a full kerning lesson, the secret to successful kerning is that each character should be visually centered between the characters to its left and to its right. (Notice that I said "visually", not "numerically"; there's a big difference.) As an example, let's use the word "Ladder", set in Adobe Caslon Pro Regular, seen below.
Notice that each letter is visually centered against the characters on its sides:
I chose this specific word because it contains one of those difficult kerning pairs, a capital "L" and a lowercase "a". To illustrate the excessive negative space in this pair, I've highlighted the gap:
To fix this, once you've kerned the type as best as possible, convert it to an editable format. If you're in a vector program like Illustrator (preferred), convert the type to outlines so that you can edit the points. If you're in a bitmap program like Photoshop, rasterize the type. The main problem with this pair is that the base of the "L" is too long to be comfortable. Using a selection tool (bitmap program) or the direct selection tool (vector program), select the whole left side of the "L"—everything except the right serif—and shift it several pixels to the right. There's no set rule for how far you should go; use your own discretion, but remember that you don't want to edit the precise curves that make the typeface so well-excuted in the first place. You can see a before/after below:
It's not a perfect solve, but decreasing the size of that gap makes that pair a lot tighter, creating the illusion that it's closer to the way the other letter pairs are kerned. It's almost indiscernible to anyone that's not looking for it, but, when it comes to typography design, minutia is key.