I'll take a stab at answering. The Celtic Cross I use is this one:
Card 1 and 2: The situation, and what crosses it.
Card 3: The root of the matter - what's the basis for it.
Card 4: The recent past
Card 5: The Querent's expectation
Card 6: Next steps
Card 7: Fear or what the Querent wants to avoid
Card 8: others' influence in the matter
Card 9: What the querent hopes - why does he want this
Card 10: Outcome.
I don't think this spread is good for general reading. It works best if there's a focus to it. A general reading will give you general answers that won't mean anything. At it's best, CC takes a snapshot of a particular situation in time. Done right, this spread gives out a ton of information. Mind you, most of what I learned and what I'll be sharing, I learned from lessons with a teacher. Books rarely go into this kind of depth.
First, you can lay the cards face down, and you read each card by itself in the order of the spread. Laying them all face-up will distract you, especially if you see card 10.
2nd, if the reader and querent have discussed what is to be asked, card 1 to 4 shouldn't be a surprise for the querent. These cards are there to basically mirror the situation as it stands now. If the querent doesn't agree to what these cards say, then the spread is wrong and needs to be struck down and started over. There's no point going further. Either the question was wrong, the querent didn't tell you the whole story, the reader got distracted when shuffling, etc.
Card 5 is the querent's expectation of the situation, which can be different than what they want. An example, this guy wants to ask this girl out, but he expects she'll say no.
Card 6 is self-explanatory.
Card 7 (fear) and Card 9 (hope) should be compatible. I've seen some CC spreads where one card was to represent either hope and fear, which is difficult to interpret. One card cannot represent both fear and hope, imo. It just can't. I prefer one card for each. Following the example of the guy asking the girl out, he could be afraid she's not in his league, and but he hopes to show off to his friends if he succeeds.
Card 8 is whoever has any influence, which you determine before you cast the spread. It could be what the girl herself thinks of the querent (is he even in her radar?). It could be one of his friends egging the querent on to make a fool of himself.
Card 10 is the outcome, for good or ill.
This is quite a bit of information already. But there's more!
Then we get into the smaller spreads contained inside the CC, which will add more meat to the reading. Over here, the aim is to compare cards within small sets of cards. A lot of it will be psychological.
Card 4 - 1/2 - 6: past - present - future
Card 3 - 1/2 - 5 : basis - present - expectation: often expectations are based on past experience. There's a history there that can't be wiped clean despite a desire to succeed or change.
Card 5 - 6 - 10: expectation - next step - outcome. Card 6 is a gateway, so to speak. Is it compatible with card 5?
Card 3 - 6 - 10: basis - expectation - outcome: similar to one above, but you look at any discordance between the reason for the situation and the next step.
Card 7 - 6 - 9: fear and hopes, versus next step. Are they compatible? Is there one card that contradicts the other?
By now, you should get some kind of conclusion of the situation and how you get to the outcome. But wait, there's still more information to be gleaned from this spread!
In this third pass, you look at the overall spread, and see what suits are there. Is there a dominance of one suit? Is one absent? Is there one number in particular that shows up in several times (3 or 4 cards of the same number is significant) Count the cards, what percentage to they represent based on 10 cards? For example, the major arcana represent 28% of the deck - so not unusual to see 2 cards out of 10 being major arcana. 3 or more could mean forces at work beyond the querent's control. For minor arcana - 3 cards or more of the same suit, or the same number, can be significant. You expect to see a balance overall. Any suit that's dominant is crowding out other suits.