These are a couple of the early replies.

Allfie Noakes  :
 Do your own thing and very importantly do not pressurise yourself, you're there to enjoy it and you want to be coming back the year after for more, The first laps are not so much about pace but getting you and your machine comfortable with the task, don't be getting into corners too early and then come out off throttle(all arms and legs as I got told hahaha), don't follow quicker people as distance travelled versus your reaction time will get you into a lot of trouble, note any places you're struggling with and if possible go and sit in the hedge and watch where on the track the quicker people are putting their bikes before, mid and on the exit. Maybe have a look at Brian Reid's TZ250 lap on youtube - the Duke video is the best, easy to watch as it's not a 1000cc missile but tells a lot about corner speed, smoothness and bike placement.

Canamant :
Although I'd been to the IOM for may years on holiday I never learned my way around the course as a course, just roads between places I wanted to be. Over 22 years I had done precisely 3 laps on a motorbike (one of which was a GN125) before I took off down Bray Hill in 2012. My way of learning the Course was to have a day with an experienced competitor in the van where we broke the course down into chunks where you could ride it as you saw it and then bits where you really had to slow down, and bits where you could ride through flat out even though you couldn't see through it.  I never watched on board laps as it all looks flat and featureless to me.  Joey Dunlop once said the went from places he liked to places he liked.  That is probably as good advice as you'll ever get.  Be assured though that it does all come together once you start putting in the laps.  It also gets addictive.  I was on a real downer in 2014 when I didn't get a ride in the Manx or the Classic Races.  Really depressed.

SPL001 :
As a 2014 newcomer I spent a lot of time watching the Milky Quayle/ John Barton lap (I could almost recite the whole thing by the middle of August) along with a few other on boards like the vendetta racing stuff, and kamil Nolan's laps.......all on YouTube.

I would strongly recommend you get in touch with the Mike Hailwood Foundation (Jim Hunter) as they run really well organised newcomers weekends. You get lots of laps in cars with people who know what they are doing round the mountain course, some very useful information, Scroot tips, etc and get a few beers with people in the same position as you. The weekend probably cost me £200 including flights and we were lucky enough to get some money back from them when we entered and started (almost covered the weekend costs).

Best of luck.