1. Proper Surface Preparation: Before applying plaster, ensure that the surface is clean, dry, and free from dust, grease, or loose particles. Any imperfections or cracks in the substrate should be repaired or filled with suitable materials to create a smooth and solid base. This step is crucial to prevent cracks from forming later.

2. Quality Materials: Invest in high-quality plastering materials. The choice of mortar mix, sand, and additives should be appropriate for your specific project and environmental conditions. Using subpar materials can lead to weaker plaster that is more susceptible to cracking.

3. Adequate Curing: Proper curing is essential to allow the plaster to dry uniformly. Ensure that the plastered surface is kept moist for an adequate period, as specified by the manufacturer. Rapid drying due to excessive heat or wind can result in cracks. Use curing compounds or wet cloths to maintain moisture levels.

4. Control of Thickness: Maintain a consistent thickness of plaster throughout the application. Variations in thickness can lead to differential drying and, subsequently, cracks. Use guides or a straight edge to ensure uniform thickness during plastering.

5. Expansion Joints: For external plastering, especially on large surfaces, consider incorporating expansion joints. These joints allow for the natural expansion and contraction of the building due to temperature changes and prevent cracks from forming. Consult with an architect or engineer to determine the appropriate placement of expansion joints.

By following these tips, you can significantly reduce the risk of cracks during both internal and external plastering, resulting in a smoother, more durable finish for your construction projects.