Eliminate the noise entering the op amp. Insert filters in the path of the op amp's input-signal lines and its power-supply lines. Insert high-pass filters in lines that have high-frequency noise signals. Insert low-pass filters in lines that have low-frequency noise components.
Reduce the op amp's ability to amplify noise. Insert a filter in the op amp's feedback loop so that the gain of the amplifier decreases at noise frequencies that are higher and lower than the signal frequencies you are trying to amplify.
Separate the traces or wires that enter and leave the op amp so that they are as far apart as possible to eliminate cross-coupled noise between inputs. Don't overlap traces or wires that connect to the op amp's pins. Use wires and traces that are well shielded from each other.
Place a power source, such as a voltage regulator, physically as close as possible to the power supply pin of the op amp. This will ensure that the voltage at the op amp's power pin is well regulated, reducing the probability that noise will be injected into and amplified in the op amp.
Simulate the op amp and the associated circuitry it is connected to with a noise analysis simulator. Vary the op amp's gain resistors and filter components to evaluate how changes in these component increase or decrease noise levels. Vary the dimensioins of the traces in your design and the position of the components to see how the layout of the design affects the noise levels in your op amp. Change the component values and layout in your actual design to the optimum values you found in the simulation and verify that they reduce the noise in the actual circuit.