How to clone a chili pepper plant?
Here are 9 steps to clone a chili pepper plant:

1.) Prepare a cup with water. Start by filling an opaque cup about halfway full with fresh water. Use filtered drinking water and be sure it is cool/room temperature.
2.) Identify a young branch. To increase your chances of a successful clone, always choose a branch that is actively growing. Avoid woody, stiff branches. Look towards the top of the plant for a medium sized branch that is still soft and green.
3.) Make a clean cut at the base. Using a sharp blade (I like using sewing scissors for their precision), cut the branch at an angle below a node. Leave at least 2-3 nodes on the branch above the cut. Always use a diagonal cut to increase the wound’s surface area. This helps the cutting root more quickly.
4.) Remove flowers, fruits & some leaves. To help it direct energy towards producing roots, remove all flower buds, fruits, and most of the foliage. Leave a few leaves (3-5) per cutting, but remove the rest.
5.) Submerge cut end in water. After cutting the branch, move it directly to your prepared cup of water, ensuring at least one node is submerged. Some growers like to use rooting hormone to stimulate the plants to grow roots faster. If you plan to use this, dip the cut end and lower node(s) of your branch in the powder before placing it in water. Some hormones can be dissolved in the water.
6.) Keep in indirect light. Avoid too much direct sunlight or powerful grow lights. Instead, keep the cuttings in a bright room with indirect sunlight (a few feet from a sunny window or grow light works well). Too much light can cause more leafy growth or burned leaves.
7.) Watch for dried leaves. During the first few days, keep an eye out for wilting leaves. If you leave too many on the plant, they can become stressed. Remove a few more leaves in this case, but do not remove all the foliage.
8.) Replace water as necessary. Over time, the plant will drink the water and some will also evaporate. This can happen pretty quickly if it is dry. I like to replace the water every week or so, or as needed. If you just top off the water, it can be susceptible to mold and algae growth, so replacing it is preferred.
9.) Once roots form, transplant to soil or hydro. After a month or so, some cuttings may start to form small roots. Allow them to develop to at least 1-2 inches before moving to a growing medium.

You can easily clone several branches from the same plant, as long as they are healthy, actively-growing branches. Keep in mind that some pepper varieties will root much more quickly than others. It comes down to that individual plant’s physiology.
Can I use this process to clone other nightshade plants like potatoes and tomatoes as well?
Yes, the cloning process is similar for many plants, including other nightshade plants like tomatoes and potatoes. The key things to focus on are:

1. Choosing a healthy, actively growing branch or shoot
2. Making a clean cut below a node
3. Providing the right environment - enough humidity, indirect light, and replacing water regularly
4. Watching for root development and transplanting once roots are 1-2 inches long

The timing may vary a bit depending on the specific plant and conditions. Tomatoes and potatoes can take a bit longer to root than chili peppers. But overall, the process is quite similar. The most important things are choosing the right growth to clone, keeping the environment suitable for rooting, and being patient until new roots form.
What are the different methods of making cuttings or clones?