2. The first sentence is correct. The comma comes before the conjunction (“and,” “but,” or “or,” for example) in a compound sentence.

the first sentence is correct. if you ever need help with sentences like that, think of the compound sentence as two simple sentences.

“I like the color red but. My favorite color is blue.”

since people often begin sentences with conjunctions (though this is incorrect), it would make more sense for the comma to separate the sentence before the conjunction.

“I like the color red. But my favorite color is blue.”

that mistake is more likely to be seen than the one above.

the “natural pause” is before the conjunction.

2. I agree with those that say a comma is not necessary but sometimes a comma is used for emphasis, e.g.:

I told you to wear the red sweater not the green one.

I told you to wear the red sweater, not the green one.

Never start a word with “and”. It links two phrases together. If there is no second phrase then it is not needed. You could use “also,” instead.

A comma is not needed in either of those two sentences. “I like the color red but my favorite color is blue” is gramatically correct. A lot of people use commas when they are not needed because people put a natural pause there. That is not always the case.

The first sentence is correct – you want your ideas to be together (talk about red – comma – talk about blue).

The comma is used to connect two smaller sentances.

I loke the color red. My favorite color is blue.

the word but is connecting the two so you do not need the comma.

and, Hee hee is it never good to start a sentance with and but you may if you are following thru within a paragraph.

ps, the comma goes after the and.