What problem should I Look for first on my starter?

Bolted to the belhousing by 2 bolts on passanger side of vehicle. 1 main power wire (hot at all times) and a signal wire(small only hot in start position grounded by nuetral saftey switch) check to see if both connections are tight and also check the 13 mm. hot lead at back of alternater. make sure you disconnect the negative battery cable in case you accidently ground you wrench