More than 5 million Floridians already have cast ballots, but voters who have yet to make their choices should make every effort to make it to the polls Tuesday. There is too much at stake to sit this one out, from control of Congress to the governor’s race to local contests. Aside from the high-profile races for U.S. Senate and governor, here are four areas where Tampa Bay voters can make a real difference. Congress. Just 23 U.S. House seats need to flip for Democrats to take control from Republicans. Three key Tampa Bay races, one for an open seat and two with Republican incumbents, could be pivotal. In District 12 covering north Pinellas County, all of Pasco County and a portion of northwest Hillsborough County, Democrat Chris Hunter is the strongest challenger that incumbent Republican Gus Bilirakis has faced. The Pasco County resident is a former FBI agent and federal prosecutor who would better represent the district on issues such as health care and the environment.In District 15 covering eastern Hillsborough and two other counties, Democrat Kristen Carlson is uniquely suited to fill the vacant seat left by retiring Republican Dennis Ross. The Lakeland Democrat has a rich background in government, business and agriculture, serving for years as a senior attorney and general counsel for Florida's Department of Citrus. She is a far better choice than Republican state Rep. Ross Spano.In District 16 covering the southern Hillsborough communities of FishHawk, Lithia, Apollo Beach and Sun City Center, Democrat David Shapiro offers a well-rounded agenda. The Sarasota attorney would focus on middle-class issues, from protecting the Affordable Care Act to diversifying the jobs base. He promises to be more visible in Hillsborough than the Republican incumbent, Rep. Vern Buchanan of Sarasota.Florida Senate. Two Tampa Bay races are the key to Democrats gaining seats in the Republican-controlled Senate. In District 18 in Tampa, Democratic Rep. Janet Cruz has made her strong support for public school funding the key issue in her race against incumbent Republican Sen. Dana Young. In the open District 16 seat that covers north Pinellas and part of Pasco County, former Rep. Amanda Murphy is a conservative Democrat from Pasco who would be better on health care and other issues than former Republican Rep. Ed Hooper of Clearwater. If Democrats win these two seats, they could narrow the gap to 22 Republicans and 18 Democrats in the Senate and be poised to take control after the 2020 elections.Hillsborough County Commission. The Democratic candidates for two open countywide commission seats offer broad bipartisan appeal. Mariella Smith and Kimberly Overman are small-business advocates who want growth to pay for itself, a common-sense approach that should appeal to Republicans and Democrats alike. Their plans would grow Hillsborough in a more sustainable way. Smith and Overman also bring a competency level and sense of openness that would raise the public's image of local government.Pinellas School Board. Up to three members of the seven-member board could be new after Tuesday’s election, and that would be one too many. In the open District 2 countywide seat, former Tarpon Springs City Commissioner Jeff Larsen stands out for his clear ideas and enthusiasm. In the open District 6 seat that includes northeast St. Petersburg and south Pinellas beaches, Matt Stewart has a strong command of the issues and would bring a younger voice as a 38-year-old human resources manager and foster parent. In the District 3 countywide seat, incumbent Peggy O’Shea should be re-elected because of her experience and strong grasp of the district’s finances.