Setting up your gears from scratch.

Campag make a useful little plastic tool (UT-FD120) to help with lining up the cage with the cogs. There's no reason it wouldn't work with Shimano:

http://www.comtat.co.uk/products/836.htm?gclid=CMuE4pDomMwCFbgy0wodFOsBcw

The packet contains two, one for 53t and another for 50t. Really useful.

For a SRAM Yaw FD the main difference is you don't want to set the FD parallel to the big chainring. Instead, there are marks on the top of the FD cage. You want to line up these marks parallel to the big chainring instead.

The effect of doing this is, the FD cage will effectively have a few degrees of "yaw" with respect to the big ring. In other words, it'll be toed in.

GCN have a better explanation with a separate video dedicated for Yaw FDs.

There are lots of videos on YouTube for reference, but I'll walk you through the steps of adjusting a front derailleur from scratch here. I'm assuming you have a Shimano front derailleur.

SRAM's Yaw FDs have a slightly different setup, particularly regarding the angle of the FD cage.

1. Undo cable anchor bolt - it's hard to make position adjustments to a front derailleur with a shift cable held in tension. If you have a barrel adjuster, wind it in all the way clockwise, then back it out about four turns counterclockwise.
2. Loosen the FD mounting bolt or clamp band and make sure the outer cage plate is 1-2 mm away from the large chainring. Make sure it's parallel to the big ring too. (Here's where SRAM Yaw FDs are different.) Once position is dialed in, clamp down on the bolt or clamp band to hold it there.
3. Since you have no cable tension on the FD, your chain should automatically be on the small chainring at this point. Shift to the largest cog at the back.
4. Inspect the inner plate of the FD cage and make sure it has 0.5 mm of clearance between it and the chain. Basically you want the inner plate as close as you can, without chain rub. If not, take your Philips screwdriver and turn the "L" limit screw - it's usually the inboard one. Clockwise turns move it outboard; counterclockwise turns move it inboard.
5. Set the shift cable into the cable anchor bolt and pull as tightly as you can. Then tighten the bolt to lock the cable down.
6. Shift to the smallest cog at the back.
7. Try to shift to the large chainring via the left shift lever. Usually you won't have enough cable tension to do this successfully. Add cable tension by turning the barrel adjuster counterclockwise, backing it out a little at a time until it finally completes the shift.
8. Inspect the outer plate of the FD cage and make sure it has 0.5 mm of clearance between it and the chain. Basically you want the outer plate as close as you can, without chain rub. If not, take your Philips screwdriver and turn the "H" limit screw - it's usually the outboard one. Clockwise turns move it outboard; counterclockwise turns move it inboard.

After that, you're done. On my bike at least, after these adjustment steps, the trim function should already work properly.

You won't be the first person to do that!

If you read up on how to replace all gear cables that will be what you are essentially trying to do, it's time consuming (or was for me!) but once you understand how things work you'll be in a good place going forward.  I don't appear to have bookmarked any useful links I'm afraid.