Whether your goal is collecting medicinal plants or foraging for wild foods, a few approaches seem to work well (or sometimes not so well) for me.
1. Start with no expectations. I like to check out an area with no intentions of looking for a specific plant or food. Just enjoy yourself, bring a camera and take notes. Collecting the plants is not your objective. When you are not looking for anything in particular, you will be amazed what you will find, you are also a lot more likely to cover a larger area of land. If you start off on a quest for one particular plant, and you have never been there before you may be disappointed and you may also pass up some really good finds. Also, if you happen to run across that particular plant, and you begin to gather, you may find later that there was a much bigger patch or better quality patch else ware. Because you were not familiar with the area and you did not scout it out, you missed it. Use that day for taking in the plants that are there, cover a large area, take mental & hand written notes of the area and where the plants are located. Return at a later date (maybe even the next day if you found the perfect plant) when the plants are at optimum harvesting stage. This is also a good time to get permission to collect if it's private property.
2. Going out with the intention that you will just collect anything you find. This includes any edible or medicinal plant you know. Then when you get back home you improvise and cook up or dry, tincture, any thing you bring back. This can bring many pleasant surprises and off the wall recipes that you would not normally plan. Sometimes you may even hit the jackpot! Study up before you leave and bring a good plant key ( this is why I like the picture before you gather method, you can take plenty of time identifying, and the plant remains there for when you return) Remember the more you know the more you can gather!
3. Spontaneous eating of wild foods or sampling of medicinals. This occurs when you are in the middle of some other activity like a company picnic for example. You cannot control yourself when you see some sort of wild delicacy and you indulge! This is great, especially when bosses, or unknown employees see you and your spouse has to explain that you have obsessive compulsive wild food consumption and collection disorder. Your excitement is enough to justify any weird looks of disapproval from others.
4. Going on a medicinal or wild foods quest for a single plant. This is sort of like gambling and may or may not be rewarding if you are hyper focused on the one plant. You go on a quest for the one plant that you know (or suspect you know) is in season for that region and habitat where you are looking. Say you are looking for huckleberries. If you do find them, they may not be at the harvest stage, or someone or something may have gotten there before you. A lot of disappointment can occur if you search for one plant to the exclusion of all others. You could come home short or with nothing at all. Not to mention the disappointment you have caused the other plants that you ignored that were calling out to you to be gathered.