I don't know how much of this is true to the B18a1 but the B18b1 has two 5 mm holes in the cam and the cap that retains the cam (the one right next to the cam gear). With that you have your cams set to top dead center. As for the crank, there are 4 marks on the crank pully. Three right next to each other and one thats by its self. Line that up with the little tab on the timing cover or the arrow on the oil pump and you should have it set. The books says to then rotate the crank 4 to 6 times until you reach TDC again. Turn the cam gears 3 teeth counter clock wise (The way honda engines rotate). Then tighten the tensioner to 40 ft lbs.
Like I said, this is for the B18b1, I don't know the changes from the a1 to the b1.
And as TheOtherDave said, I would replace the belt and water pump.