im Grothmow and I know my vel build is pure power and knowledge is power and vel is knowledge

for runes I go 1x magic pen and 1x ability power and 1x ap scailing ratio for qiunts vel has bad ratios but amazing ap base so the magic pen really helps alot

for marks I do 9x magic pens prime focus for vel
for seals I do 9x health wither u have an ad or ap they both have heath in common
for glyphs I do 9x abilty power still is a mage but not prime focus

building in cool downs is better since we have a max in lol so we focus first mana magic pen, ap, and survivabuility then look at ur team lol is a team game don't forget that. be the vel, learn and adapt.

try to last hit to get mana from dorans ring and that jungle mastry turret hug the only thing that vel players mess up at ithe over extend turret hug if u have to ur not a badass ur a smart***. stay close but not too close to the action to get xp. remember w can go through minions so if the enemy is boxing him or herself up use w. I if they are far back use vels q to get around minions and hit the enemy.

pros:
great damage
spamming
true damage
mana sustains with this build
great teamwork

cons:
squishy
slow
bad ratios

vel has great teamwork, stay in the back and spam and weaken foes. true damage has nothing but health between death. with mejas you can use assist to help you and feed your team.

the best jungle in my book to help vel is a tank with a lot of cc and can jungle fast to help other lanes. volbear helps a lot

for a good support I recommend braum he is tanky and has cc and can help people suvive

for adc the best for me hands down was trist she can engage then u spam right after she jumps in

for top, gnar really helps he can be that chaos the enemy team cant get a read on which helps team fights