So dont rate or comment this is just how i play blitz

Dont bother your self with runes yet, 1st buy champions you desire to and then go for the runes, Dont buy runes until you hit lvl 30. Also dont start playing ranked games if you dont have runes.

These runes work for me

-Your Rocket Grab cost a lot of mana so dont waste it. w8 for an excellent opertunity to pull, but also dont be scared to try cuz only thig that will make you better is practice.

-Dont be greedy and rush for a kill (Minions are your main source of gold) well if you have carry leave the minions to him

-Best way to hit your rocket grab is to line up with the enemy

-Also get used to playing with smartcast for quick reactions

-Always pull squishiest target, not tanks

-Try to pull your enemy when they are in the choke points (choke points are places where your enemy has limited number of escape ways) (example: somewhere in the jungle)

-When going for a pull Use Your W to speed up and then grab, but also care to line up with the enemy

-When you hit Your Rocket Grab, use your E to knock him into the air.

- when going 1V1(which i dont recommend) dont use your ult
immediately because your ult's passive will deal the damage for some while and then use your ult to finish off enemy

These are some tips I could have tought of, they are not all of them but i couldnt remember all of them.

Your items shouldnt be exaclly the same very single game. Because you buy items that you need If ADC or any AD is fed go for more ARMOR, if Ap is fed go for more MAGIC RESIST, But always have this ratio 70% Magic resist/ 30% armor OR 30% Magic resist/ 70% Armor, OR in the 3d case 50/50 (balanced)

This set of runes masteries and items work for me now Once you get more experienced you can combine your own things and experiment what works best fr you.