For reasons, I had to recently delete a hierarchy where all 1726 nodes in the hierarchy were locked ha. So a quick google popped up Tyler Hurd's blog post. Really super useful so I thought I'd post it here too, so I can find it easily if I need it.
Side note....I need to figure out how to get code to format properly on Weebly haha.

import pymel.core as pm
for obj in pm.selected() :
     if pm.lockNode(obj,q=1,l=1)[0] :
          pm.lockNode(obj,l=0)
          print '%s unlocked.'%obj
     else :
​          print '%s not locked.'%obj

Small detail but I finally googled how to pick-walk through controls when you have offset and skd groups in the way ha. https://www.creativebloq.com/how-to/create-custom-rig-controls-in-maya

Select the controls you want to pick-walk through and hit 'Tag As Controller'. Then select the child control, then the parent control and hit 'Parent Controller'.

I never knew but turns out you can change the thickness of NURBS curves. Create a NURBS circle or something for your control, and at the bottom of the shape node adjust the Line Width attribute. Job done. Amazing haha.

The skeleton needs to be as straight as possible in a T pose.

Just learned something new! When you parent constrain an IK handle to a control, you can't always undo when you move the control. Or when you zero it out. But if you parent the IK handle under an empty group and then constrain the group instead, you can undo IK movement ^^

Found this out after a quick Google from here.

Found on the Mocappys website.
Rotation order is evaluated in reverse, so if rotation order is XYZ, the X and Y axes will follow the Z axis. Or, putting it a different way, the Z axis will drive the Y and X axes. Whereas the X axis will only affect itself. So you want the most important axis (the one the character will use the most) to make the others follow it, and so be the last axis. Check the example below for how to figure out rotation order.

Using the hips/pelvis as an example, obviously this will depend on how you're oriented you joints : 
X = Bends forward and backward
Y = Turns around
Z = Bends side to side

Putting them in order of importance : 
Y = Turning around
X = Bending forwards and backwards
Z = Bending side to side

So the rotational order for the hips/pelvis would be best set to ZXY.

This is another fantastic tutorial from Zeth Willie. I take no credit for any of this.

• Create bound shoulder, elbow and wrist joints, attached to the clavicle. Duplicate twice to make FK and IK joints chains. These should also be attach to the bound clavicle.
• FK and IK joints should orient constrain the bound joints.
• Create RP IK on the IK joint chain.
• Make FK and IK controls.
• Make 5 locators
  • arm_pv_dummy_loc : Place this where the pv ctrl is and parent constrain it to the FK shoulder joint, maintain offset on.
  • wrist_fk_dummy_loc : Parent constrain this to the wrist FK joint, maintain offset off.
  • elbow_fk_dummy_loc : Parent constrain this to the elbow FK joint, maintain offset off.
  • shoulder_fk_dummy_loc : Parent constrain this to the shoulder FK joint, maintain offset off.
  • shoulder_wrist_fk_midpoint_loc : Point constrain this to the shoulder and wrist FK joints, maintain offset off.

Something I really struggle with is OK-ing topology on a new model. So I'm going to be keeping a list of things to check. Right now it's super short because my memory is terrible. I will add to it as I discover more.

• Close edge loops around knuckles would be helpful when trying to figure out where knuckle joints are meant to go. Also they help maintain volume.

Super small little entry but wow it makes a difference ^^ I've found it particularly useful when you have to add a joint to a hierarchy that's already skinned.

• Display > Wireframe Colour
• You can select multiple joints to apply the same colour to all of them at once

After seeing the below tweet by Riham Toulan, I figured out how to use the nodes she mentioned to make a similar system in my own rigs. This may or may not be how Toulan set it up, but this is how I've done it so far.

• Make a poly cylinder for the neck. You can shape it later to better fit the shape of the neck and head of your character. You could even use a low poly version of your character's actual neck and head.
• Make a nurbs circle or curve around the top of the collar. You'll want to rebuilt the curve so that the U value goes between 0 and 1.
• Decide how many points you want to put around the collar. Put them at the base of the collar where each part of it will rotate. We'll call these bound joints for now.
• Make a number of locators equal to the number of bound joints. Attach them to the curve using the pointOnCurveInfo node, and place them above each joint by adjusting the U value.
• You may need to create a locator that sits in the middle of the ring of locators. This isn't attached to the curve, but will act as an 'up' pointer for your aim constraints in a sec.
• Aim each bound joint at the appropriate locator on the curve, and use the central locator as the up vector.
• Now make a floating joint for each locator on the curve. We'll call these control joints.
• Select the control joints, shift select the curve and bind skin.
• Now when you move one of the control joints it'll pull the curve and the collar joints will rotate accordingly.
• Make a group for each of the control joints.
• Select the neck cylinder. Deform > Muscle > Muscles / Bones > Convert Surface to Muscle/Bone.
• Select one of the groups that has a control joint in it and Deform > Muscle > Self / Multi Collision > Rig selection for KeepOut. Do this for each group.
• Select the neck cylinder and one of the newly made cMuscleKeepOut nodes. Deform > Muscle > Self / Multi Collision > Connect Muscle to KeepOut.
• You may have to change which direction the joints move away from the neck in. You can do this in the attribute editor of the cMuscleKeepOut nodes.

Voila ^^