Obviously in the shoe! But where?

A friend suggested this:
-Draw a horizontal line across the top of your big toe
-Draw a horizontal line across the bottom of your little toe
-Cleat goes in the middle of the space between the two

Is that right? Any other good ways of working this out? Thanks!

On the bottom of your shoe…

Put them where ever and go ride then adjust until they are comfortable . Maybe start in the middle as such then go try them.

Is that right?

No. Has your friend even looked at the bottom of an SPD shoe?

What Chris said.

Sit with your legs dangling off the edge of a table.
Try and take note as to which angle your feet are pointing.
Thats a good rough angle at which to attach the cleats to the shoes.
Put them in about the middle postion at the above angle.

If we are talking road / CX bike then might be best to get a proper bike fit.

Make sure the pedals are on the loosest release setting for the first few rides.
Make sure you unclip one foot BEFORE you stop.
You will end up on the floor at some point as you forget to unclip.

As a rule of thumb, and as a starting point only, you want the pedal axle to be underneath your bunion joint. Put the shoes on and mark the edge of the sole where this joint sits. Line the cleat up with this mark. As above, the angle your foot falls to naturally is important, otherwise you’ll knacker your knees and/or hips.

Depending on your preference, you may want to slide the cleat forwards or backwards to get your instep or toes nearer to the axle, but it’s all down to how it feels most comfortable

That was nicely put Cloudnine. I’d add that if unusual pain in your leg, normally your knee, you probably haven’t got it quite right. Play about and you’ll be able to work it out. It’s hard to get it perfect first time.

PS Cloudnine are you one of the frame builder guys that was at Bespoked?

No.. wish i had the skills to make frames though.

Had quite a few knee/ankle problems when i first set mine up a few years ago.
I have some soletec custom insoles, a shim on one shoe and quite a strange cleat angle on the other but seems to work well now. IME Seat angle and seat height seem to also become more critical once you get clipped in.

Excellent thanks guys!

You will end up on the floor at some point as you forget to unclip.

This. Usually at very low speed because you forgot to unclip just before you come to a stop. Always in front of people / cars at traffic lights / pelican crossings. 😳