When you do call in to begin announcing your arrival, it will help everyone in the pattern-and approaching the airport - if you're good about indicating how far out you are and in which direction.
Ideally, you'll plan your descent from your cruise altitude to arrive at least a couple of miles from your destination at pattern altitude so you're not descending into the pattern. At pattern altitude it'll be easier to scan for other traffic in the pattern, since they'll appear on the horizon and not be obscured by ground clutter.
It takes a little simple math to determine when to begin your descent. If you're going to descend at 120 knots with a descent rate of 500 feet per minute, it will take you four miles for every thousand of feet you lose. Let's say you're cruising at 8,500 feet and the airport elevation is 500 feet. You'll want to be at pattern altitude (1,500 feet) about three miles from the airport. You'll need to lose 7,000 feet. Four times seven (thousand) is 28. You'll need to start your descent when you're 31 miles out from the airport, so you'll be at 1,500 feet three miles from the airport.
I'm always surprised when an accident report indicates that the pilot failed to file a VFR flight plan. Many flight schools require that students file a flight plan on every cross-country flight and it's a good habit to get into. A VFR flight plan is an insurance policy that will pay off if you have to land off-airport somewhere.
Unless you're heard from within 30 minutes of the time you indicated in your flight plan as your estimated time en route, a search will be initiated to locate you and your airplane. If phone calls to your destination and other likely airports along the route don't turn up your presence, a search and rescue operation will be initiated. If you're landing at a tower-controlled airport you can ask the controller to close your flight plan, otherwise, you'll have to call the 800/WX-BRIEF number to close it.
If it's been a while since you've made a VFR cross-country flight, you're missing out. Plan the strategy carefully but fly tactically, taking into account changes that inevitably occur, and you'll find a VFR cross-country a nice reminder of why you started flying in the first place. Turns out, you really can get there from here, and getting there is often more than half the fun. Enjoy!