[quote name='themaster20000']Finally got Demon's Souls.What are some good tips for a newcomer to this?[/QUOTE]
Like Icebeast said, Royal class to start for sure.
I'd also recommend using a spear as your primary weapon. You can keep your shield up while using a spear, so when first starting out it can really help you if your timing is off and they hit you while you try to hit them. It's biggest downside is the very narrow forward range. Since it stabs straight ahead, it's not good for mobs, so make sure to lure out enemies one at a time (a generally good idea in the game anyway)
Eventually, I'd recommend moving onto a different weapon with a wider swipe range. Makes it easier to hit enemies, bosses, and crowd control. Master the parry (or riposte if you really want to be fancy, with a rapier, but I think that's too risky) and counterattack. You do this with L2 (I think?) just as the enemy is about to hit you. If you attack after a pary, it's an automatic critical.
Don't eat any "soul" items you find unless you are in the nexus so you can actually use them to level up. Eating them in a stage just increases the risk of you dying, not being able to make it to your bloodstain, and losing them.
Speaking of souls, do not eat boss souls. They are used either for forging unique weapons or getting unique spells / miracles.
In general, suicide in the Nexus (careful not to land on anyone! See next point). You have less health in soul form (half, but there's an HP ring that boosts that to about 3/4 max), but cannot be invaded, and dying in the regular levels in body form shifts it towards black tendency (which makes the level incrementally more difficult). It's technically easier to shift to Pure Black, get the Pure Black bonuses, and then shift to Pure White (as killing the boss of the stage is a huge white side bonus) but I personally didn't care about such things, at least in my first play.
Anyone you kill in the Nexus is dead. For Good. Until NG+. So do not kill Stockpile Thomas, etc. You've got a good heart, don't let them take it from you!