Give the bag a job
Decide what it will carry before choosing a pattern: a library book, a small project, or a few market finds. That choice helps you judge size, fabric weight, and handle length. If you are new to a machine, use inexpensive woven fabric for a practice version. You can make the more decorative bag after you know how the plain one feels in your hand.
Follow one complete set of instructions
Choose a published pattern and read it all the way through before cutting. Janome's canvas tote project provides cutting measurements, strap placement, seam steps, and a flat-bottom finish. It includes pockets and sturdy fabric, so you might choose a simpler beginner pattern if those layers feel like too much for a first afternoon. The important thing is to follow one tested method for the size and construction you choose rather than mixing measurements from several bags.
Gather fabric, matching thread, scissors, pins or clips, a marking tool, and the needle recommended for your fabric and machine. Sew a short straight seam on scraps first. Practice guiding the fabric without pulling it, then test how the machine handles the layers where a strap will attach. Follow your machine's manual when changing a needle or clearing a jam.
Notice the part you would change
Carry the finished bag on an ordinary errand. Do the handles sit comfortably? Does the opening let you find what you need? Would a pocket help, or would you rather keep the next bag lighter? Write down one improvement while the experience is fresh. A second version can change just that detail.
The photographed bandana patchwork tote shows how far a familiar shape can go with a different fabric and lining. It is an example of a finished bag, not the Janome pattern linked above.
Where to start
Borrow a machine or take an introductory class if you want someone nearby for the first setup. Read the full tote method before buying fabric, then keep the first version small enough to finish and use. For another project that starts with a single technique, try learning one stitch.
I hope this finds you well,
Scott