Varied Practice:

Practicing a skill or technique with only one set of variables will produce a memory ‘engram’ (or brain ‘program’ if you like) that will be reliable when used in real life only when those same variables present themselves. The danger comes when we try to use a skill in a different scenario.
If the skill is only practiced in one scenario then the skill – however good – will only be reliable when that scenario happens.
Take a skill or technique and practice it with as many variables as possible using different environments and equipment. Only doing this creates a truely all round skill that is reliable in all environments.

Practice should be fun and even messing about with a skill is valuable learning –
Try rolling a kayak with someone hugging it!