Monopods are OK if you are walking and shooting a lot but they are not light if they are good ones. Try bracing your camera in the same way you would shoot a rifle for accuracy. That means both elbows against your chest with one hand out front holding the lens barrel as far out as comfort allows and one holding the body. Its a little awkward at first but you will find a comfortable position.
If you feel uncomfortable with that like me, try the string method which I actually prefer when a large rubber band is added to the string for tension. Take a string and tie a 2 or 3 ounce weight on one end. You can use a 6" stick if you prefer. On the other end, tie the string to a heavy rubber band like the ones that use to come with bundled vegetables at the super market. Make the string the length of from your toe to slightly above breast height. Put one foot on the stick or weight and the rubber band end around your lens barrel. This will not work so well with auto focus lens that the barrel length changes but for others you will find the tension on the lens barrel will do better than a monopod because it allows more free movement up and down as well as sideways with practically no weight to carry around. The stick or weight on the bottom makes it easier to keep the string taunt and find it without looking for it. That way you don't have to take your eye off a bird or whatever your shooting. You can experiment with different size and strength rubber bands as well as string lengths to suit your comfort. I gave my heavy monopod away. I used it more as a walking staff for a while and even an adjustable ski pole was better for that. The only thing you need to be aware of is the lower end of the string can snag on bushes or whatever. The rubber band serves not only to keep tension on the lens to reduce or eliminate shake but also adds some give if the string snags on something. That way it won't snatch your camera out of your hand. That happened to me one time about 30 years ago and that's why I added the rubber band. Its relatively easy to stop shake with string but some positions you may want to shoot from are best accommodated by have some elastic material in the line.