Just go in with confidence. Have a cross country planned very well, using your method you used on your Private Pilot one you already did.
Show knowledge of knowing your fuel consumption during climb, cruise, and descent and have a plan for how long you will spend in each. Don't forget you'll need to land with a 30 min. reserve. Base your overall consumption on those.
Show knowledge of takeoff and landing runway length needs. Plan on using your GPS, cross-checked with Pilotage/Dead-Reckoning and Sectional marked with your course line and visual checkpoints. Draw a corridor 2.5 NM each side of your C/L and circle all tall obstacles or high terrain that falls in the 5 MI corridor. Complete an FAA 7233-1 (Flt Plan) and put it on your clipboard with your folded sectional. Fold it so your whole course is visible if possible.
An exceptional student will get the coord's of their checkpoints off the sectional and store them in your GPS as waypoints. Then your Pilotage/Dead-Reckoning Flight Log should EXACTLY COINCIDE with your marked sectional and the GPS moving map.
IF YOU COME IN WITH THAT PRE-DONE, it will be unlikely a Sport DPE will ask you to plan another. If they do, just duplicate the process on the new assignment. Sometimes a DPE will deliberately assign you a CC that will penetrate a Prohibited Area or active TFR to see if you are sharp enough to detect it and not let it happen. Sometimes they will assign you a course that requires both sides of the sectional to see if you have enough common sense to figure out how to plot a straight line that crosses the edge while keeping the correct Mag Course.
If you come in with all this, there will be no doubt you meet the PTS for all non-flying tasks related to CC. To demonstrate you have the flight skills, just be confident, takeoff on the planned CC with a sure-footed attitude. Punch your stopwatch and record time on your Flight Log as you start your roll.
Don't be in a hurry. You have 10 minutes before you reach your 1st checkpoint. You can't reach FSS until you have some altitude. Once established in a stable climb with some altitude, or even after on course at cruise altitude, call __122.25, 122.3, 122.35, 122.45, 122.55,
122.6, 122.65, or 123.65___ Radio and activate your Flight Plan by reading ONLY THE INFORMATION YOU WROTE on the 7233-1 to them, in numerical order. They will talk in plain English conversation if you desire but exceptional students will just rattle the info off like a machine gun and the FSS people WILL get it. Adjust your activation time to when you started your roll a few minutes ago.
HINT #1: Very few checkride cross-countries are completed. Typically the examiner has you takeoff, go to your first checkpoint about 10 miles away, and divert SOMEWHERE as they are attempting to distract you with something like an open window or dropped keys. For that reason, know approximate direction and distance to the nearest airport from checkpoint #1. Be prepared to turn to that heading and estimate arrival time without the GPS. He may turn it off.
When it comes to a distraction, there are two kinds: Those that matter/and those that don't. If his distraction don't matter - tune it out. If it does...ask him if he will fly a constant altitude and heading for you while you handle the distraction. Transfer the controls properly with verification.
Hint #2: In light of hint #1, when you activate your flight plan after takeoff, tune the correct freq'. Pretend to make the radio call but do not key the mike. Play the role of FSS Attendant and YOU. Answer yourself. This will keep you from forgetting to cancel it after landing while demonstrating your sure-footedness in the whole process to the DPE.
Here's an example: "Macon Radio November Five Zero Zero Wiskey Wiskey" when They acknowledge, say "Activate Flight plan, VFR, November Five Zero Zero Wiskey Wiskey, Experimental Helicopter, Slash X-Ray, Eight Zero, Kilo Victor Papa Charlie, One Zero Zero Zero Zulu, One Zero One Two Zulu, 35 , Kilo Victor Papa Charlie - Direct - Kilo Romeo Mike Golf, Zero Zero Two Five, Bryan Cobb 168 Simpson Circle NE, Cartersville GA Seven Seven Zero- Six Eight Seven- Zero One Four Four, Kilo Victor Papa Charlie, Two, White Black, Kilo Romeo Mike Golf."
I promise you, if you practice this process with your CFI on every CC flight y'all go on, and practice it on your solo ones too, you will be confident doing it on your checkride and your DPE will be blown-away. It will be obvious to them that you are well versed in the knowledge and aeronautical ability for the DPE's requirements pertaining to Cross Country Planning, Cross Country Flight, Electronic Navigation, Navigation by Pilotage and Dead Reckoning, Dealing with Cockpit Distractions, On-The-Fly Diversions Even When Electronic Nav Devices' Batteries Die.
Just Sayin