Are there any simple ways to tell if somebody has a risk for stroke?

Yes: Family history of stroke. Hypertension. Diabetes. Elevated cholesterol. Smoker. Excessive alcohol use. Coronary artery disease. Carotid artery disease. Cardiac arrhythmias.

Medical history: Yes, if someone has a history of diabetes, hypertension or prior strokes/tia's, they carry an increased risk of having a future stroke. Additionally, atrial fibrillation or a history of abnormal blood clotting are risk factors for stroke.

Many risk factors..: Prior stroke/mini-stroke, heart attacks, smoking, diabetes, high blood pressure/cholesterol, atherslerosis, infections, medication uses/chemo, connective tissues disease such as lupus/rheumatoid arthritis etc...Having more of these factors increases the risk...Thus prevention and treatment of existing illness as best as possible... Good luck.