Strength

It is likely that a higher Extrusion Width, up to 150%, will create stronger prints.

Adding Model Textures can improve Strength.

Also see Generative Design - Overview.

Annealing

Annealing can improve performance on PETG but is not recommended for PLA.

Supporting Documentation

Videos:

• 3D Printing with PETG - How does the printing temperature affect strength? || Setup & Tips

• MUCH STRONGER 3D prints due to LESS COOLING! Testing PLA & PETG

• Triple (x3) your Layer Strength by Annealing 3D Prints in Plaster!

• Which color of PLA is the strongest?
  

Articles:

• The BEST 3D printing material? Comparing PLA, PETG & ASA (ABS) - feat. PRUSAMENT by Josef Prusa

• MUCH STRONGER 3D prints due to LESS COOLING! Testing PLA & PETG