"EFFECT" and "AFFECT"
"Effect" is a noun meaning result. "Affect" is a verb meaning to influence. Ex.: The new policy had a significant effect. The weather can affect our mood.
"PRECEDE" and "PROCEED"
"Precede" means to come before in time or order. "Proceed" means to continue or move forward. Ex.: The introduction precedes the main text. After the break, we will proceed with the meeting.