I did a bit of internet research on plaids, and found some useful tips.
1. Plaid comes in two types, even and uneven weave. Basicly, in the even weave, the pattern repeat on the cross grain and the grain are the same distance, so you end up with squares. In an uneven weave, you end up with diagonals - particularly unsuitable if you're hoping to use it on the bias. To check whether a fabric has an even weave, fold it diagonally so the cut edge is along the selvedge. The pattern repeats should match up.
2. Be super careful when cutting out. Decide which piece to use as a base, and cut that piece. The match up the next piece, choose a specific line of the pattern and mark that on. Place the pattern piece on the fabric so that the lie matches the mark.
3. Avoid fabric creep! I never baste, but I think this is one occasion I'll have to! One way of doing this is to iron under teh seam allowance on one piece, place it on top of the other as it will be in the finished garment so you can see exactly where you need to match up. This is also an occasion I should probably try out my walking foot!
4. Avoid curved seams - this is gonna be interesting in making a victorian dress! but you can see on the picture that horixontally at least the plaid is beautifully matched at what appears to be a back seam on the bodice.
Now all I need is an extra 10 hours day....