Firstly, you must realize that there are some things that are like your planet, but many aren't. For instance, i don't believe you have viruses that come alive given correct conditions, or parasites that eat the eyes of those unlucky enough to get them. Anyway, with that grossness out of the way, you must remember, that if you need help, the Guardians will be there to assist you (most of them are quite fond of humans).
Now, there is one thing you must always remember, new things are discovered every time we go farther into the forests, deeper in caves, or higher up the mountains, you never know what will come around the bend. So be vigilant, be careful, and most importantly, goodness gracious, have some common sense please! If it looks like it can hurt you, it will. If it doesn't, it might, and for your first adventure, please, stay out of the water! But, now that that's over, go explore! And make sure to attend the Christmas celebrations!