Normal strategy I'd suggest is first, if your opp goes first, if they have set cards on the field, play spells MP1 then wait till MP2 for traps in case they use a malevolent catastrophe or MST.
Also, if you play on DN, try your best to win RPS. But don't take too long or people will be ragey.
Traps to have would be: Mirror Force, magic Cylinder, Sakuretsu Armor, Dimensional prison, Spells are Dark Hole, MST, Night beam, Monster reborn (banned September 2013 til Dec 2013), and Heavy storm (Also banned until Dec 2013 TCG only)
Also, if you play real life, if your opponent you know really well, read the cards and expressions. What i mean like that is that if you know they are a defensive player, then don't attack all at once and get mirror forced. But if you know they are overconfident you should go do a massive otk if you can.
All I can think of because you didn't give a specific deck or type of deck, ie agressive beatdown, stall, troll, defensive, etc. Marshmallon or Spirit reaper serves you well in stall and defense decks. Alexandrite Dragon, Axe Dragonute, Gene-warped Warwolf help a beatdown deck. Good staple xyzs include Number 39 Utopia, Blackship of Corn, Maestroke Djinn, and Wind-up Zenmaines.