Here ya go . . . done it many times in many states:
1. DO NOT PASS GO, your client FIRST needs to hire a QUALIFIED INTERMEDIARY. You need to know how much he can and NEEDS to spend, and what he can and cannot buy.
2. Depending on the briskness of your market AND HIS, he may not be timing the deal properly if his duplex is not already in escrow. Remember you have 45 days to ID the replacement property and 180 to close (them all) AFTER the closing of the duplex.
3. Remember that you will need 1031 verbiage in your Contracts: "Buyer/Seller to particpate in Buyer/Seller's 1031 Exchange at no monetary cost to (the cooperating party)"
4. Timing is important since you're purchasing multiple properties . . . keep an eye on the calendar and allow longer escrows for the downleg (see 5)
5. HAVE BACKUP PROPERTIES identified, JUST IN CASE one falls out. When you exchange, you have to 'exchange up' so if it's a 500k downleg, and you're buying 2 275k uplegs, if one can't close you'll need another to avoid tax on the profit. 
6. YOU talk to the intermediary and get THEIR TIPS for a smooth deal . . . they are your guru!

Ah, Grasshopper...follow the advice of Candice A. Donofrio.   Real gurus = a good idea.  Gurus masquerading as experts = not so good.  Get the right help to best serve your client.  

You work with an attorney who specializes in 1031 exchanges... that's how you keep it from going off the rails.

As Candice A. Donofrio wrote. The Best Advice!

Get with a good Qualified Intermediary in your area.

No airbags .. follow the advice of Richard Weeks 

Get your broker involved if necessary or partner with another agent experienced in this type of real estate transaction.

decades ago, I did one and each party had their own attorney..... it ran very smoothly.... don't play attorney.... even if you think you've mastered this type of exchange, I assure you, you haven't unless you have legal background....

Any tips?

Hmm, if you have no experience..

#1. Hit the books
#2. Find someone with experience
and finally, understand 1031s are timing critical. Don't offer outcomes that the time-line will not support.

Candice A. Donofrio covered it.

hand-hold the whole thing and walk it in and out of escrow & into the sunset

Hire an expert, 

Your client needs a good lawyer with 1031 experience

You should definately speak with a lawyer who specializes in closing them. Changing states, going from one type of property to another all add difficulty 

Either take a class on 1031s which are offered all the time or hook up with someone who does them.

Best of luck

In Georgia the only difference in the real estate end is to make sure that the closing attorney for the sale/buy transactions are both qualified to hold 1031 funds.  Beyond that the buyer/seller works with their own CPA on budget amounts and I only have a clause to ad to the contract that it is a 1031 exchange.

 If you have not already gotten a 1031 exchange company involved, do so immediately. Their representatives can answer all questions for you and your client. Get them involved before your client negates any advantage offered by doing the exchange.

Follow the advice of Candice A. Donofrio 

A good qualified intermediary in Florida is an excellent first step. Candice A. Donofrio provides an excellent outline

Did you ask this before like a week ago?

Contact a 1031 attorney who's up on the deal.

Tim,

Like Candice A. Donofrio explained, you need an intermediary!  Wishing you success. A

Make sure your client is receiving professional advice.

They need a good administrator and you (or them) need to find a good agent to partner with in Florida.

Stick to the schedule. 

A former realtor sold her home for 1+ mil and went around US. Told me she got one in Dallas for 90K. Reluctantly make an offer for a 2 br condo for 550k across from Apple Space Ship.  It was instantly rejected. Then drove 75 miles to East SFBA. Headed for Denver to do basement bargain hunting. You have just 45 days to identify and 180 to close all deals. Not much time to f&c# around. If you identified 3 properties that you like to do exchange from and can not get them. Out of luck.

You are better off showing them new homes or vacant homes to close. 

Don't look to active rain for legal advice.  I already see some answers that are not true.

Buyer needs to hire an intermeditiary to show them the way...

Eve

Refer them to a good agent in FL who understands 1031 exchanges and who will communicate with you and the attorney for a smooth transaction.

Enlist qualified professionals to help with this.

I am reluctant to answer your question because I do not practice real estate in either state. Just make sure your client does not deposit the money from the first sale into a personal account - it will no longer be allowed in the 1031 Exchange.

Tim Ball if your client has not already lined up a CPA or other tax professional in each of those states you may wish to aid him/her with that part of the transaction.

Hope you referred it to someone that knows how to do a 1031, and then you should not be worried.

I recommend you read and know all the rules and get Inermediary involved now. First American would be my choice. I would get the title officer and theri CPA to verify what the basis is and what was depreciated to compare IF an exchange is the best. They need to have money to travel to Florida. Buying sight unseen is not a plan.  If you price the California duplex correctly it should sell in 40 days - DO not go into this alone if this is your first one. The listing/sellers will blame you if you land them a taxable event.  A 1031 exchange has hard and fast time lines which make this a juggler's worry.

I just did one with 1031 in Calif and colorado and no problem