Primary income via W2 with some 1099 earnings as well

I have a full-time job (W2) and also do contract work (1099) as a side gig.  I need to know whether my current approach to taxes is appropriate.  At present, I increase my state and federal withholding from my W2 employment to accommodate the additional untaxed 1099 earnings.  I do not pay estimated taxes (no quarterly taxes).  Instead, I enter both the W2 and 1099 earnings when I file my taxes annually.  Is this approach correct or should I be doing something else?