Be prepared! And be careful not to do
Your good deed, when there’s no one watching you…
Tom Lehrer, “Be Prepared”
But how hard it is to be good even when someone is watching!
Here at the Lionel Hampton School of Music, we have a very picturesque Victorian building, red brick covered in ivy, with Tudor and Gothic-inspired architraves, leadlight windows and the like. It’s very pretty, in a spooky, Harry Potter-ish sort of way. Like much picturesque Victoriana, however, it lacks really good soundproofing. This means that I get to hear my colleagues in the surrounding offices–piano, flute, bassoon, saxophone–practising and teaching all day. (They’re all wonderful musicians, so hearing them is really a pleasure.) They can also hear me through the thin walls, and so can the students who like to sit and study in the alcove opposite my office door.
The top question students ask me, whether it’s about playing the cello or the class in ear training and sight singing that I teach, is “How should I practise?” As their teacher, I feel it’s important for me to set a good example to them, and practising within their earshot does keep me on my guard against inefficient practice. It’s so easy to lapse into lazy habits, such as wasting one’s time running a piece “from go to whoa” (when I was younger, I thought the phrase was “from go to woe,” which is sometimes true!) without really dissecting the parts that are going wrong. So much of the time people gloss over the parts they can’t really play, thereby training themselves always to do it wrong–or at least to have a bad scramble instead of a cleanly-executed passage. Consider this notorious run from the beginning of the Schumann Cello Concerto:

(By the way, this is such a hard thing to have to play in the second phrase of a concerto–thanks a bunch, Herr Schumann. By comparison, the robust opening of the Dvořák Concerto seems positively easy.) Inexperienced players are often so terrified of it that they drop off the fingerboard altogether, or practise it too slowly for it to be any use up to tempo, or simply repeat it again and again, never getting it quite right. In a performance, they know “the hard bit’s coming up!” and tense up, thereby further increasing their chances of missing.
In this particular passage, two practice habits can really help. One is to remember that your strings run in straight lines. This seems almost too simplistic to be worth mentioning, but you sometimes would never guess from the strange Chicken Dance-style flapping movements some cellists make that the goal was to move one’s hand in a straight line from one point to another.This being the case, it makes sense to keep the left arm supported with elevation (notice I don’t say “Keep your arm up,” which to my mind sounds forced and tense) so that you have the least possible distance to travel between third position on the G string to thumb position on the D and A. If you have to wrench the elevation of your arm up to get over the “cusp” of neck position and thumb position, you’re likely to miss. If your arm’s already elevated, all you have to do is move your fingers–smoothly, of course–and release your (hopefully loose and relaxed) thumb from the back of the fingerboard to rest lightly on the harmonic in the middle of the string. Easy! (Hah.) In summary: use your arm rationally and economically; no Chicken Dances allowed.
Second technique: on a micro level, that is, on the level of your finger pads that have to touch the strings in the right place, I recommend breaking the run into small components, stopping on certain notes until you can land on them in tune, then adding one more note, like this. (If you can’t see the whole graphic, try clicking on it for a complete view.)

This is the sort of thing I want students to hear me play, first of all so they know that I’m practising what I preach, and secondly so that they can hear that the ability to play hard music isn’t some blessing bestowed automatically upon the fortunate, but a learned skill like any other.