(Steve Marcus for The Washington Post)

College football bowl season kicks off Dec. 20 with five games and continues through Jan. 12, when the College Football Playoff semifinal winners meet to determine the national champion. Here’s what you need to know before making your picks. (All odds as of Wednesday, Dec. 17, and taken from the consensus odds at VegasInsiders.com.)

First off, if you’re not reading the blog at SportsInsights.com, you should be. It’s essential (and the blog itself is free). Over the past week or so, the folks there have written a few posts with some great tips on making bowl picks. Here are a few pieces of wisdom gleaned from these posts.

Unranked teams usually are good plays against ranked teams

Casual gamblers usually overvalue ranked teams, meaning there’s value to be had by picking the unranked teams. According to SportsInsights, unranked teams are 39-25 vs. the spread against ranked teams over the last 64 bowl games that feature such a matchup.

There are a few bowl games that fall under this scenario (using the final Associated Press rankings): Colorado State (+3.5) vs. No. 23 Utah in the Las Vegas Bowl on Dec. 20; Duke (+8) vs. No. 15 Arizona State in the Sun Bowl on Dec. 27; Oklahoma (-3) vs. No. 18 Clemson in the Russell Athletic Bowl on Dec. 29; and Notre Dame (+7.5) vs. No. 22 LSU in the Music City Bowl on Dec. 30.

Expecting a low-scoring game? The underdog is usually a better play. A high-scoring game? Pick the favorite.

Pay attention to the over-under total when making your spread picks. “Favorites have gone 88-63 ATS in games with a total of at least 56, while underdogs have gone 78-66 ATS in games with totals of less than 51,” David Solar of SportsInsights.com writes.

Per VegasInsider’s lines, 25 bowl games have totals higher than 56, while six have totals lower than 51 (and one, the Military Bowl between Virginia Tech and Cincinnati on Dec. 27, is right at 51).

SEC and Sun Belt teams historically have been good plays. Big 12 and MAC teams, not so much.

Per SportsInsights, SEC teams are 46-34 ATS in their last 80 bowl games and Sun Belt teams are 23-18. On the other end of the spectrum, Big 12 teams are 30-41 ATS over their last 71 bowl games and MAC teams are a wretched 11-26.

Watch for reverse line movement

As Solar explains here, it’s good to keep tabs on teams receiving less than 35 percent of public money, because they can be good plays under certain situations, namely when the line moves in a way you wouldn’t expect. For instance, UCLA was only receiving 32 percent of spread bets as of Dec. 16 for their Alamo Bowl matchup against Kansas State, so one would expect the point-spread number on Kansas State to rise. But the Wildcats have gone from 1.5-point favorites to a pick ’em at certain bookmakers, indicating that sharp money is coming on on the Bruins.

Other teams to watch:

UTEP (+10) vs. Utah State in the New Mexico Bowl on Dec. 20. The Miners are receiving just 28 percent of the money but have gone from 11-point underdogs at some shops to 10-point underdogs.

Notre Dame (+7.5) vs. LSU in the Music City Bowl on Dec. 30. The Fighting Irish are receiving just 34 percent of the money but have gone from 9- or 8.5-point underdogs to 7.5- or 7-point underdogs.

Do coaching changes matter?

It’s a fairly small sample size, but over the past three seasons, bowl teams with interim coaches are 9-11 ATS. That’s not a statistically significant edge for either side.

Other trends of note

Boca Raton Bowl, Dec. 23: Marshall (-10 vs. Northern Illinois) is 7-1 ATS in its past eight bowl games, but ended this season on a 0-3 ATS skid.

Heart of Dallas Bowl, Dec. 26: Louisiana Tech (-6 vs. Illinois) was 10-3 ATS this season. TCU and Western Michigan were the only other teams to finish with 10 ATS wins.

Quick Lane Bowl, Dec. 26: Rutgers (+3 vs. North Carolina) is 6-1-1 in its last eight bowl games, while the Tar Heels are 6-3-1 in their last 10.

Military Bowl, Dec. 27: Cincinnati (-3 vs. Virginia Tech) is 3-8 in its last 11 bowl games but ended the season on a 6-0-1 ATS run.

Holiday Bowl, Dec. 27: USC (-6.5 vs. Nebraska) is 8-2 ATS and straight-up over its last 10 bowl games.

Music City Bowl, Dec. 30: Notre Dame (+7.5 vs. LSU) is 2-10 ATS in its last 12 bowl games and hasn’t beaten an SEC team straight-up since 2005. The Tigers were 7-1 ATS this season as a favorite.

Belk Bowl, Dec. 30: Louisville (+7 vs. Georgia) is 9-1 ATS as an underdog since the start of the 2011 season.

Cotton Bowl, Jan. 1: Michigan State (+3 vs. Baylor) has covered in three straight bowl games and is 8-1-1 ATS in its past 10 gmes as an underdog.

Rose Bowl, CFP semifinal, Jan. 1: Florida State (+9 vs. Oregon) was favored in every game this season but was just 3-10 ATS this season, one of the worst ATS records in the country. The Seminoles haven’t been an underdog since 2011, going 24-25 ATS over that span.