The perfect cards to use in syncro decks are easy to summon five stars so you can get out stardust dragon and red archfiend dragon.
When stardust dragon is out use cards of safe return so you can draw cards every time it comes back from the graveyard.
If you have the cards, try to put mix a syncro deck with a dark draw deck.Use dark tuners with a mixture of dark cards and combo's like Destiny hero dasher, malicious and destiny draw (destiny draw for the draws,Dasher for its special summon and malicious fro d draw and its effect), use cards like allure of darkness, gravekeepers spy and return from a different dimension.
Use dark world cards Sillva and Goldd with cards like hand destruction and dark world dealings, then once there special summoned merge them with the tuner card to create which ever syncro monster you want.
Use cards like dasher so that when you draw a monster card you can special summon it,then normal summon another card(tuner) and merge them together.
Always even when your deck isnt tuner or syncro have a stardust dragon in your extra deck just incase your opponent has a syncro deck and has some useful tuners in their graveyard you can reborn and use to make stardust dragon.