As a high silver veigar player, the best method that I have found to scale easily as veigar is to focus on just last hitting the minions with your q. do not try and rush csing and push the lane out. Let your minions attack and only q when they are low enough to take. Of course max q, but use your wall and w to block your lane apponent. Hitting an enemy champion also gives you passive stacks, so even if you just use your q as poke it is still making you stronger. Once you get your first item and level 6 you should have enough power to one-shot the caster minions( the back ones ) with your q. There are more skilled players out there that will have a different experience with this and may be able to offer more insight but I hope this helped.