labor leisure trade off
My suggestion would be to take the habit of fully writing down and then solving formally even the simplest model. Yours is a static one,

$$\max_{C,L} U(C,L) = CL,\;\;\;\; s.t. C = (24-L)w$$

since we silently assume that the individual cannot consume more than his income. Here $L$ is leisure, not work.

Inserting the constraint into the objective function,

$$\max_L U[C(L), L] = (24-L)w\cdot L = 24wL - wL^2 = w(24L - L^2)$$

This permits you to see that the wage doesn't matter for the optimal allocation (it will matter, for the level of utility attained). This may sound counter-intuitive... It is, and it has to do with the category of functions to which the specific utility function belongs to. In other words, it is an unrealistic aspect of the model introduced by a mathematical choice we made.  

The above has a straightforward solution for a maximum.

(PS: Has Walras been notified that his name is used in such a manner?)