Talismans from a plant you allied with, think of the rowan tree which haves a tradition of protection. I start visiting the tree long before the berries grow: in the end of the winter to be able to watch the complete growing process. I bring with me attention, intention and maybe some water or manure to help the tree growing, The moments of the visits can be daily, but it is possible to carefully choose those moments. (Under influence of planets, or chosen by divination, use your own method)
For harvesting the rowan berries I pick a special moment too, but it can be that nature chooses another moment: every growing season is different and you need to accept that, Doing so, you will develop a relationship with that tree also. After harvesting I dry the berries and after that I chain them on a tread with a little help of a sharp needle. You can add dried root parts of mandrake too, preferably a home grown plant.
Another method: choose blackberries in your neighborhood to harvest from and harvest some blackberries itself and the thorns. Choose the thickest and prickiest thorns you can find. If the plant makes scratches on your skin and you bleed, it is a plus and maybe even a prio. Dry the thorns. Cook the berries till you have the black juice. Cut 3 branches of the bramble and make a hoop from it. If it cracks you need start over again with everything with another plant! Before picking the blackberrie stuff you have find some white sheep's wool. Clean it, spin a thread of it and make a little pooch of it in your preferred method. Paint the pooch with the blackberrie juice and vinegar of urine. Handwash it, dry it. Then take all those thorns you collected, put them in pooch and close the pooch by sewing. On full moon lay down the hoop (your circle) and place the pooch in the middle to make it gain more power. There you have another strong working talisman. Needless to say that you have your intention in mind the whole time in this whole process. Make sure you choose blackberries from a place that is not so cultivated by modern humans. I have some special places: a bronze age burial place and a place where there is a folk story about a giant who lives behind a thorny hedge. If you are open for folklore and history you can find places like that yourself.
(this evening I open a discussion thread about natural talismans in the witchcraft part of the forum)
(edited because of forgetting a word)