Action priority, by this I mean the most productive order in which to do things in your turn. We have all done it while playing Scrolls, drawn into a card we can really use but have already moved our units, or cast a spell and spent our resources, then draw into something which would have been far better for the situation. What I plan to try and outline with this post is what is the most optimal sequence to do things in your turn.
Decide what to sacrifice, you should be sacrificing every turn, unless you have what you believe to be a perfect hand for the situation drawing an extra 2 cards at the cost of another is generally better and can keep you in the game. It's never good to go into "Top Deck" mode where you must rely on the next card you draw.
If you are even thinking of using any cards which let you draw more cards, do it before you do anything else. Don't move your creatures!
After you are done drawing look at the available options to you; think through the best use of the cards in hand and the state of the field. Work out if you need to move your creatures, and where, to get the most out of them. Just sit and observe the field.
Move your creatures into position.
Cast your spells and end your turn.
So to break it down into some more straight forward steps:
2. Draw cards.
3. Observe & Think.
4. Move creatures.
5. Cast Spells
Whilst by no means this is THE way to make the most out of your turn, for new players following this hopefully you will be able to reduce the amount of mistakes you make. As any of the higher ranked players will tell you, all it takes is 1! That's right! JUST 1 misplay or creature out of position, and you can lose the game.
Hopefully this will provide you new guys with the ground works to get the most out of your turn and reduce the mistakes you make to a minimum.
You have 1 minute 30 seconds for your turn, make the most out of it and don't rush into your decisions.
Combat, unit values, units attacking, and units being attacked is explained in this guide aimed at new players.
How to deal with the hard trials in Scrolls when you have a small library.