What are the symptoms of conjunctivitis I should be looking for?

Redness and Discharg. Conjunctivitis can be due to many causes: bacterial, viral, allergic, chemical, etc. The most common in probably bacterial and causes redness, mucus discharge and sometimes foreign body feeling or frank pain. Sometimes there is associated blurred vision from the mucus discharge. Bacterial conjunctivitis will frequently cause enlarge a painful lymph node just in front of the ear on that side.
Redness, irritation. Conjunctivitis, usually a viral infection of the eye lining, causes irritation, foreign object feeling, overflow of tears and obvious redness of the eyes. If there is pain or change in the vision it could be a more serious kind, or something else. Your ophthalmologist can sort this out.