Tips for sewing straight ribs?

[Digger]

Hey guys, i just learnt how to use a sewing machine and have a problem:

So i have started something that will at some point look like a cumberbund

And now i'm supposed to do 6 stitchlines to create 5 ribs dead centre.
Do you have any tips and tricks to help make those lines evenly spaced and straight?

I used pencil to draw lines before but those are really hard to remove afterwards.

Advice

[Chopper]

You can get tailors chalk in various colors. It's designed to mark lines for straight sewing, but should come out of the fabric easier than pencil. 

https://www.amazon.com/dp/B00V07YRJC/ref=cm_sw_r_cp_awdb_t1_hGVZBb89ZMC8W

[masteroftheforce]

I used painters tape on the inside of the cummerbund.  That way I didn't have to worry about it bleeding onto the fabric and being seen later.  Just be sure to keep track which side is the "good' side, the closure on the back is right over left.

[Dart]

Also, one thing I can suggest which might seem a bit odd... when sewing it, don't go slow. I find that if I'm being too cautious, my stitches can get crooked.

Practice on some scraps going faster. You'll notice that if you can concentrate on keeping straight lines, it's much easier.

[cheesewhoopy]

Chalk is a good route as suggested. Or you can use pins to map out your line and just follow the path. If you have a good eye you can do a straight line without putting anything on the fabric. 

[cheesewhoopy]

Also if you do mark lines, mark them on the inside not the outside. If your settings are right on the sewing machine the stitch will look the same on both sides. Then just trace over your lines with the sewing machine. No one will ever know they are there. 

[762s]

congrats on learning on how to sew ... wish i would have learned sooner than i did
 

good suggestions above .... but, they make pencils that will wipe away with abit of water.. head to your local sewing/fabric store

[ScottF]

I used a blue water-soluble sewing pen and drew very light lines, then dabbed them off with a damp wash cloth.

[Digger]

Alright i followed the exact same course and i believe it worked out well.
Went to a sewing store and the lady suggested the blue pen.

marked the lines on the front side and just painted the thread over it.

and after using a spongebob those lines were gone in a breeze.

Thanks for all the advice guys, im on to the codpiece next!