Sample Full Build
Ghost + Flash is a fine alternative in mid lane.
Brand is a lane bully in most mid lane match-ups. His base damage is incredibly high, and as such, magic pen, CDR, and utility are higher priority than pure ability power, in many cases.
Doran's Ring: Usually the best opening item for Brand. If snowballing, or confident in your ability to kill your lane opponent several times early, can opt for 2x or 3x Doran's Rings instead of Morellonomicon. Will hurt your DPS, but help you get to your combo burst items faster.
The Dark Seal: Can greed for one early. Don't recommend it though. Brand has a habit of trading 2 for 1 on enemy ganks.
Morellonomicon: Gives you incredible lane pressure and great DPS in scraps and fights.
Sorcerer's Shoes: Magic Pen is Brand's best friend. Buy these almost always. Ionian Boots of Lucidity are acceptable, in rare cases, particularly vs tanks in lane, but that's about it. You'll usually be CDR capped late game without them any way.
Rylai's Crystal Scepter is a great item for helping brand bully in lane. It makes his Sear stun pretty much free to land after hitting Conflagration, allowing a free Pillar of Flame as well.
Liandry's Torment is the best damage item on brand. It chains well with Blaze and his high base damage, and even better with Rylai's Crystal Scepter.
Void Staff, again, helps boost Brand's high base damage, and allows him to burst tanks as well.
Zhonya's Hourglass is usually the best 6th item on Brand. It allows him to negate enemy burst damage, and survive while waiting for another spell combo to come off cooldown. It also CDR caps him, in most cases.
Abyssal Scepter is a good magic resist alternative to Zhonya's Hourglass, particularly if you need the magic resist portion early in lane. Not as good over-all, but still a decent alternative.
Rabadon's Deathcap is the item of choice if you feel completely safe late game, and just want more damage.
Guardian Angel is the item of choice if Zhonya's Hourglass isn't enough to save you. That's about it. Don't buy if you need more damage still.