Creating a flat sketch is a common technique used in fashion design and technical design. Here are the steps to create a flat sketch:

Start by gathering your design ideas and inspiration. Decide on the silhouette, details, and fabrics you want to use.

Draw a croquis, a basic figure template, on a piece of paper or on a digital drawing software. This will serve as the base for your flat sketch.

Use a pencil or digital drawing tools to draw the basic outline of your design on the croquis. Be sure to include all the details, such as seams, darts, pockets, and closures.

Add shading and texture to your sketch to indicate the type of fabric and any other design details.

Label each element of the sketch, including the fabric, color, size, and any other important details.

Repeat the process for all views of your design, including front, back, and side views.

Once you have completed your flat sketches, review them to ensure accuracy and make any necessary adjustments.

Share your flat sketches with your team, manufacturer or clients, or use them to create technical packs, which are detailed instructions for garment construction.

Remember, creating a flat sketch takes practice and attention to detail. With time and practice, you can master this technique and create professional-level designs.