My suggestions:

First, remember that your client almost always assumes your competence - for better or worse. If you have bothered to show up here, and especially if you have reviewed the comments here and in the archived threads, you are likely better prepared than most of us were for our first inspection.

Drive by the property before the inspection, and plan your exterior and roof access strategy in advance. I like to get up there and get a close look at all roof penetrations if possible, but I also take no chances if I'm not comfortable with roof pitch, access or condition - as my wife frequently reminds me, "Dead inspectors write no reports".

Bring spare batteries for everything.

Bring a second, inexpensive flashlight as a backup.

Remember to record the water heater and HVAC thermostats settings before you re-set them, and remember to reset them after testing.

Probably 70% of the significant damage I find is water related, and that's what I would be most alert for.

I suggest taking the following pictures, at the highest resolution your camera allows, and making SURE you get them (use the review function form time to time to insure you are getting them).

1) Wide views of all exterior walls.
2) Wide wives service entrance and meter areas, close up of meter/service panel.
3) Wide view of all visible roof surfaces
4) Wide view of all visible attic areas
5) Wide view of all visible crawl space areas
6) Access limitations to areas you cannot inspect - it's *very* important to document and report this.
7) Wide views of all mechanical areas (furnace, boiler, air handler, WH, etc.) from all accessible sides.
8) Close ups of all "capacity plates", including model and serial numbers and capacities.
9) On all electrical panels, wide shots w/ and w/o deadfront, close ups as necessary to show all interior areas and the circuit directory, another wide when you have everything put back together.
10) Whenever possible a wide view of each FP, shot up chimney with damper open, and sides and back of firebox, and hearth.
11) At whatever resolution is appropriate, individual pics of each defect you intend to report - you won't include most of them in your report, but they will enable you to review what you saw in detail.

I use Photoshop Elements to improve picture quality as required - it's *astounding* how much detail it can pull up out of shadows, etc.

Take as much time as is available to prepare your report (likely, on a Saturday inspection, no one *really* needs your report 'till Monday morning), and first concentrate on clearly and accurately reporting major defects - no one is likely to sue you over a dripping faucet - and then go back and fill in minor items as time allows.

Good luck!