Slightly overheating, what should I check first?

I would begin this diagnosis by checking for a coolant leak. It can leak externally or internally. This can be done using a cooling system pressure test.

I would also check the level and condition of the engine oil and perform a compression test and a cylinder leak down test to verify the integrity of the head gasket.

Just to add to this one you need to wait for a reply on the first question you asked instead of just asking another question. When you say the temp gauge got to the line before the red if you mean it got to the 3/4 mark on the gauge that is normal. Thats when the fan usually comes on in that car.