Sivir is a good tracker in summoners rift and also fast movement speed.First skill help to make fear to enemies when they come to attack you,that help because in first minuites need crypting for coins.The only problem with sivir: She spend a lot of Mana!! So no use all time skills,and try to never attack in air,your attack must damage your enemy! That help to immobilize the game,the method for first minuites: dont use skills all time but prefer use simple damage to crypting,only if enemy come closer or be near to crypt,then use second skill or first,the other way to success in first skill,you must run back when you attack,or avoid the enemy that you attack only crypts to feed and when you have open the skill with blue lines when he come closer,then attack.Never try to kill someone before make third build,is early.When you build and bloodthurster,then you are ready for kill,play back from other players and when have mass attack from all or from 3-4 players then use second skill,also the Ultimate skill use it when someone have little health to grab him and kill him,and if need to escape from trap when you have little time.
Thanks.