What do you mean Brawler Raelynn? She's a sniper!!?!!?!!!!
This is what you may think now, but her kit includes many items good for dueling. You're still gonna wanna take the build that will give you the best couterpush, though.
Start with Sniper damage and solar on hit to farm up solar for the rest of your build. Also take cooldown reduction on snipe.
You're going to want to make Timerift do damage for 1v1ing people and also take the extra damage shot after deploying timerift if you are a high enough level. Also takie increased slow on timerift.
For the blaster take Skull Bracelet, Monkey Hand and Lucky Cat Air Freshener for more killing power and for farming faster.
Finally, take Powerpills Turbo, Med-i'-can and her boots. If you play it right you will never die.
Start with Snipe and get as many last hits as possible in the lanes. Next get Solar on hit and health. Take Monkey Hand early for if you get some early kills. ? Depending on how aggressive the enemy is, you may want to pickup health and regen early to survive pushes. Otherwise, just max out your sniper row. Once you've maxed the Sniper row and survivability row, start maxing out your Protoblaster. ? I save timerift for last because I feel that it is most useful for lategame for winning duels.
Play Style and Tips
Dont be afraid to use snipe whenever it is off of cooldown to push droids or whatever you need it for.
You can make snipe shoot a bit early just by clicking the shoot button.
It is very easy to get multiple last hits on neutral creeps if you need health with Snipe.
If you get extra hp early it is easy to get early kills on enemies with low hp because Raelynn's Protoblaster has so much dps without any upgrades.