Do you have an affinity for a particular herb?
Have you been drawn to certain crystals?
Maybe you collect rocks that always seem to catch your eye.
These are each invitations to cultivate a relationship with these beings and their unique medicines. Perhaps you have already studied a bit or have begun to work with them and want to take things deeper.
There are a good number of methods that you can gradually get to know your new allies with or dive right into a full immersion experience. Here are a few of my favorites.
Dreaming:
Take a fresh sprig of the plant, a crystal or the stone you want to work with and place it under your pillow (or inside the pillowcase if you are worried about losing it) Thank them for sharing information in your dreamtime. This may come through directly where you meet the spirit and have a lucid dream of asking questions or being shown energies and how to work together, or it may come through as an indirect influence of metaphor where meanings reveal themselves over time.
Ritual Bath:
Depending on the type of crystal or plant (watching for toxicity or dissolving) having an ritual bath is a lovely way to immerse yourself in the energetic medicine of your new ally, especially if you are sensitive to energy. Rose quartz, amethyst, lavender, rosemary, or stones from special places are all wonderful to bathe with. This isn't a "get-clean" kind of bath, it's a quiet time to feel subtle energy. Light a candle, do some mindful breathing, meditate, and allow yourself to notice how you feel, invite these energies into your thoughts and see how they shift.
Make a tea or water:
Again using caution around potentially toxic plants and crystals if using a direct method, or stick to an indirect method to be safest - you can transfer the energy of your new friend into teas or waters and bring these medicines right into your body. A direct method is one where the plant/crystal/stone has been washed then placed directly into your water cup, or if a plant it can be brewed as a tea. Some safe crystals for this are rose quartz, clear quartz, or non-irradiated citrine. Generally some safe plants are lemonbalm, lavender, or red-belted polypore (of course I need to advise consulting a professional for any contradictions with existing medical conditions).  An indirect method involves placing your item into a flat bottomed glass, then placing this glass into a bowl that has been semi-filled with water. Your item never gets wet, but will infuse the water surrounding the glass with its energy. Again, being thankful and respectful of the gifts being shared with you. This indirect method is safe to use for any plant, crystal or stone. If you are very sensitive you may only need a couple drops of your water or tea to feel its effects, you might choose to sip all of it slowly over the day, or you may wish to drink much over a few days.
'Shamanic' Journey or Meditation:
If you have learned the shamanic technique of journeying, or if you have a meditation practice suitable, you may glean a lot of information by visiting the spirit of the plant/crystal/stone that you are working with. You can ask for a healing, for guidance on how to work further with them, thank them for showing you just what the medicine they are offering is and importantly how you can reciprocate in the relationship.
Wearing:
Tuck your stone, plant or crystal into your pocket, into a medicine pouch around your neck, find or make a pendant where it touches your skin (some plants like Devil's Club can be dried and made into beads) In this way you are in constant contact with the medicine, the energies of this helper. Skin to skin or simply in your energy field, there will be a conversation happening as you move through your day.
Mesa/Lia Mala/Crane Bag/Medicine Bundle:
Some shamanists or medicine people carry a Mesa, Lia Mala, Crane Bag or other Medicine Bundle. If you have one of these, tucking a new stone, crystal, or part of a plant into the folds is a nice gentle way of bringing their medicine into yours. If it is right to do so, you might add this piece fully inside to work more deeply, to alter the harmony already present, and to stay as a longer term influence. Each lineage will have differing ways of working with your medicine hearth so you may want to consult an elder for guidance around this.
Saining/Sacred Smoke/Smudging:
Some plants, even certain fungi, are beautiful to cleanse and bless with while burning. You may already know how buffalo sage brings about a different cleansing than tobacco or palo santo, but you might also find rowan berries become your go-to for protection while lavender opens the door to your Ancestors. You may find that some plants instantly connect you to different healing work, helpers, or area of focus than others. Over harvesting of certain popular herbs gives us an extra nudge to look local and to our cultural heritages. What is naturally growing in abundance around you? What might your great-great-great-grandmother have burned? I have been sweetly surprised to learn certain plants coming to me have a long history of being added to sacred smoke rituals. I had been working with fomitopsis pinicola for about 20 years before I discovered some First Nations used it during smudge rituals. This knowledge deepened my respect for this powerful healing ally. Oh! how I love working in these ways!

Remember, we don't just ask and take from our human or animal friends, we also care for them and support them when they need it. The same is true for our plant, crystal or stone friends. We are entering into a spiritual relationship, they may become sacred objects and part of your medicine basket, we need to always treat them with respect and honour. Never leaving them laying around or placed directly on the floor, cleansing and recharging them with moon or sun light, salt, the running water of a clear stream, or by saining. Feed them offerings, whisper your gratitude, sing to them, wrap them in special cloth or place them on your altar. This is a special and personal friendship :)