While I'm not a hyper-miler by any means, I do try to squeeze as much mpg out of any vehicle I own. I take simple steps to achieve this. I phrase I use to everyone is "every time you punch the gas, that "cool" sound you hear from your engine is actually quarters spilling out your tail pipe.".
I try to take highways whenever possible, I pick a lane....and stay there. I don't lane hop trying to get ahead of the car in front of you. You gained, what, 12 feet ? I pick a speed...and stay there. Speeding is a no-no, not for fear of tickets, it's that whole quarters out the tailpipe thing of which I spoke.
I check my tire pressure weekly, I don't rely on the TPMS numbers on the dash. Stock tires, no wide/bigger/aggressive tires. I put a K&N air filter in the box. I use quality fuel from a name brand station, no convenience store brands for me. Roof rails are empty, no cross bars installed, nothing strapped on top. No mileage stealing (but cool looking) light bars or light kits.
From day one of ownership, my lowest highway mpg has been 32, highest was 38. Sometimes on the highway, my tranny likes 8th gear and stays there. I manually pop it in 9th, sometimes it stays, sometimes it drops back to 8th, sometimes it never takes. Above 67 mph it stays every time.
As silly as it sounds, I use a saying from when we packed our ALICE packs while I was in the Corps. (yes, I'm that old...lol) "Ounces equal pounds, pounds equals pain". I keep my Latitude as empty as I can, nothing strapped/installed on the exterior (no matter how tempting).
You can get MUCH better mileage out of your vehicle. It's up to you. Don't drive it like you just robbed a bank, don't strap so much off-road crap on it like you're going on a 3 month expedition when in fact you are going to work every day, don't carry 300 lbs of gear inside. Yeah, it all looks cool and you're "at the ready"....for pictures. Install that crap when you DO go off-roading, take it off when done.
If you really like having an expedition-ready looking vehicle with lift kits, heavy over-sized tires, roof racks filled with gear, more lights than Yankee Stadium, that's fine, your vehicle, your rules. But you can't whine about the quarters falling out your tail pipe. YOU did it.