First, you need to describe your plant, so that other scientists will know what it looks like, how it grows, when it flowers etc. etc. A lot of the observation and research that you have already carried out will help you here. You can base your description on a lot of the questions you have already answered. In other words, find out where you are with the law before you part picking things. You might even need a permit from the local authority.
Some plants are easier to dry than others.
So only try this activity if you think your plant is suitable. Select a specimen. It is easiest to note this while the specimen is still attached to the plant. Taking a photo might be a good idea at this stage to help you later. Make a note of such things as the soil conditions, how close it is to water, how shaded it is and exactly where the plant is situated.