Prevent a blown head gasket

I just bought a 99 4dr LX with only 75000 miles on it. I plan on keeping it forever, as this is my 5th Honda and I have loved all the others I owned.

But that brings me to my question. My last two Honda's were both 1991 Civic LX's and I had to get rid of both due to a blown head gasket. One car had 213,000 and the other had almost 180,000 when they blew. I know I probably could have replaced them, but with the mileage on them, and the fact that I don't know any mechanics to do the work cheaply for me, I sold them.

So, how can I prevent a head gasket from blowing in the first place? Both of those cars I bought used with over 130,000 on them to begin with, so I don't know how well they were cared for. But I want to do everything I can to prevent it from happening now.

Does it have anything to do with the quality of oil used? I'm a fan of synthetic and plan on putting Mobil1 in the 99 as soon as I get the chance.

maitence, checking up on your car for proper oil level, and coolant, not really the type oil(5w30), just over heating can add towards a blown head gasket, manufacture defects(3.8L ford)[notorious for head gaskets] haven't heard of a problem w/ new civic and headgaskets though

blown head gaskets (on a stock honda) most often come from cooling system problem, resulting in over heating the engine mainly the head and thus warping the mating surfaces. the lessened pressure on the head gasket in a warped area (or even increased pressure) will cause the head gasket to shift around and wear out rapidly and eventually fail.
u could try running w/ gasoline an octane rating above the manufacturer's recommendation. like instead of 87 octane go w/ 89 octane. that way u will run even less risk of detonation, and therefore keep that from being an issue.
get u'r spark plugs, and for that matter all replacement parts, right from the honda dealer instead of autozone/advanced auto. yes they cost a bit more, but they were made for that exact car and engine in mind.
regularly read u'r plugs, that'll tell u a lot about wuts goin on inside the engine. get all the scheduled maintenance done right on time if not a little early. since u just bought the car and don't know how it was treated before u, maybe have all the scheduled maintenance for 75k and 90k done right now, and just shift everything forward 15k. like the next scheduled maintenance would be 105k, so do that one when u hit 90k, and do 120k at 105k, etc. a car can and will last forever, if and only if u do routine checkups whether or not u sense a problem. that way u will avoid problems by finding potential problems before they become problems.