As Charles is fond of saying - What do you think is the best way for you to practice?
Here he is probably right, this is a problem you can probably find your own best optimal solution but here are my thoughts anyway.
1. Prioritise how big an effect the focal point has on your swimming.
for example, focusing on not lifting the head is for me higher up the hierarchy of swimming faults than a straight arm recovery style.
Just as patient lead arm and not dropping the elbow on propulsion is much more important than the style of kick you do.
My own approach to these problems was to try to understand what all great swimmers had in common and what they had that was different.
Therefore its possible to swim great with a head forward position (ian thorpe, grant hackett), straight arm recovery (lots) or non synced stroke cycle (Rebecca addlington)
Its not possible to swim great without good balance and streamline or with windmill arms underwater or lifting the head to breath you just don't see it.
Once you have established which list your focal points are on, rank each list according to the impact they have on your whole stroke. E.g. if your balance is good but you struggle with 2 beat kick that will have less impact for you than a slipping lead hand.
Finally separate things you need to remember as opposed to things you need to learn. You may want to spend 6 sessions of keen focus learning bi-lateral breathing but its ok to swim 4x25 with a single focus each lap of things you need to remember,
e.g. mail slot entry, rotate with the hips, patient lead hand, tap big toes together to check you are not splitting your legs.
hope that helps.