How about these suggestions:
1. an exciting job= "it's a blast every day!" (job=blast/bomb)
3. competiton= "Welcome to the rat race!" (competition as a race) or "This isn't my first rodeo" (competition as a rodeo)
4. success= It's the luck of the draw (success with gambling or luck)
6. marriage= Love is a battlefield. (love/marriage=battle or alliances)
7. social class= She's a gold-digger or He's a ladder-climber (ladder=climbing to different social levels)
That's a start, anyway! Good Luck!
And exciting job: "Teaching floats my boat."
I always like this one. Sure it's a cliche, but the suggestion that the interest one has in what he or she does for a living gives life buoyancy is very apropos.
Stress: "I was all in knots for whole day." That's such a good image of being tightly tied with little wiggle room; it is very much what stress is really about.
Competition: "Hey, it's a dog-eat-dog world!" or "It's a jungle out there." Both metaphors express the idea of primal, animalistic struggle, which is the the epitome of competition.
Success: "The race as finally won." "Touchdown!" "His last presentation was a home run." You can't go wrong with sports metaphors when it comes to expressing success.
A goal: "We finally reached the finish line." "Yes, we found the Holy Grail." Again, it's nice to dig into sports, religion or mythology.
Marriage: "They were two peas in a pod." "Their relationship was a hornet's nest." "They exchanged rings and then entered the ring." "From day one, their theme song was Stormy Weather." Oh, we could go on and on with marriage metaphors :-)
Social Class: "They were from different sides of the tracks." "Upstairs, downstairs."
Material possession: "Until the accident, her BMW was a flying carpet ride." "His new putter was the magic wand he had sought for so long."
Hint: For metaphors, go where the greats went: the animal world, the weather, and, more recently, sports.