"Less intrepid souls will most likely put money to work tomorrow after the meeting if they stay the low-rate course. Ultimately, I wouldn't be surprised if the traders who bought ahead don't boot stocks no matter what, just being glad they got some gains," Cramer said. (Tweet This)  That could be a fantastic buying opportunity.  More importantly, Cramer recommended having a fail-safe plan in place. After all, the Fed could surprise and decide to raise rates a quarter of a point and say it will take more action going forward. If that occurs, the gains from the past few days could be thrown out the window.  So here is Cramer's game plan: If the Fed raises rates without a statement of reassurance that it is done raising rates, do not take the bait of the first sell. In fact, Cramer doesn't think he would even take action on Friday considering the amount of hot money that is betting that the Fed will not raise rates. Selling could be heavy.  If things get really ugly on Friday or Monday, Cramer wants investors to beware that various sectors will take a nosedive. Beware that they may continue to downslide with the market.  No. 1 Anything that's good for your body. That includes exercise, natural and organic. It includes Under Armour, Nike, White Wave and General Mills.  No. 2 Social, mobile, cloud and artificial intelligence. That means Salesforce, Google and Facebook.  Read more from Mad Money with Jim Cramer  Cramer Remix: Surprising stock to buy if Fed moves Cramer: Fed meeting could trigger a USD bodyslam Cramer's Fed cheat sheet: Prepare for 6 pitfalls  No. 3 Domestic retailers, as they are more immune to a strong dollar that will be caused by a rate hike. This includes Target, Panera and Kroger.  No. 4 Biotech will be creamed, as always. That could be a chance to pick up Cramer-faves Celgene and Regeneron.  "We need to stop fretting about a potential rate hike and start worrying about missing any opportunities that could be created by a Fed-induced selloff," Cramer said. (Tweet This)  Many investors fear the outcome on Thursday's Fed meeting. Yet, what they should be more afraid of is the fear of passing up an opportunity that may not come back for a very long time.
Jim Cramer wants investors to be prepared with a solid game plan of stocks to buy, just in case there is a selloff after the Fed meeting.