Guardian Angel: Grants you a bit armor and MR. If you die, you will also be revived with 30% health and mana.
Banshee?s Veil: Gives 450 health and a lot of MR. It also gives 100% base health regeneration plus a shield that blocks enemy abilities.
Frozen Mallet: Gives little AD and a lot of health. Passive gives the ability to slow enemies on auto attacks. Great kiting-item, but is purely optional
Mercurial Scimitar: Gives you a lot of AD and a bit MR. Has an active that removes all debuffs, and grants a small MS-buff for 1 second (50% MS). I usually never buy it though, I will just go till QSS.
Trinket and elixir
Farsight Alteration: Use it to scout?? dragon ,?? baron or a scary bush.
Elixir of Wrath: You can get this elixir late game. It gives a little bit AD, and as you heals you for 10% of the damage dealt.
Early game: Vayne is very weak in laning. You don?t have much mobility, and you do not deal much damage. Farm and play safely until you get an item or two. Of course, unless your support initiates. It is only safe to go all in if you are at least level 3. Don?t forget to dodge those skill shots.
Mid game: You now have a few items, you got your ult and is stronger from all the farming, and maybe killing. If you destroyed the enemy turret, stay in lane and get good vision, in case you get ganked. Remember to use the walls to condemn enemies. If you hit a stun and it?s a 1v1, go kill that champ! Avoid going solo. Just because you are stronger, doesn?t mean you are invincible.
It is now that the fun begins. Team fights will happen all the time, and you need to be there for your team. Always stand in the back and use your ultimate if you get caught or if your team plans to go all in.? Try and pick a priority target that is closest to you. One wrong tumble that gets you killed will pose a huge disadvantage to your team. Deal damage while being safe.