OK, so i wrote a book.
TLDR
- choose a location without carpet, and wear 100% cotton clothing.
- Wrist straps and a 2 layer ESD rubber mat is best. Vinyl ESD mats are not solder safe. Silicone mats are not ESD safe at all.
- A conductive surface like metal can be used instead of a proper mat, but has it's own issues and needed precautions.
- large cookie sheets make good easily setup portable work surface if a dedicated work space isn't possible.
What the material is used in the carpet, upholstery, and the clothing you wear is important. Synthetics, wool, and silk easily build up charges so you constantly end up zapping your chips as you are working on them unless you are grounded with your wrist strap. Changing the upholstery and carpet can be hard or impossible, but choosing a different location or different clothing is often possible. If I have a chance I will change into 100% cotton clothing before doing electronics work and I still use my wrist straps. Cotton builds up much less charge as one moves about.
Yes, use a wrist strap, but it does little good if the work surface isn't also tied to the same ground as the wrist strap. So tie all the earth grounds on everything to a common ground point which is then connected to earth ground. Keep the lengths of ground wires as short as reasonable. For years I used 0.25" quick connect terminals on the ends of all my earth grounding wires. They are much cheaper than banana plugs, but are much harder to plug in and unplug. For portability I have a three prong plug with only the ground wire connected. If you use the same method, test the outlet you plug it into first with an outlet tester to make sure the ground is really ground, and not floating or have live AC on it.
As already mentioned by nanofrog, 2 layer rubber ESD mats are the way to go for a work surface. There is some variance in how high of heat they can handle, and how durable the surface is, but I couldn't tell you which brand is best. The vinyl mats are cheaper, but only good for assembly and disassembly. They don't have the heat handling to handle dropped solder balls or soldering iron tips. The silicone soldering mats are insulating and NOT ESD safe, and will build up static charges if rubbed. Even the ones that say they are ESD safe are way to high of resistance to be ESD safe. Silicone is just too good of an insulator. They do have their uses when working with high heat like a hot air rework station, but bear in mind they are not ESD safe. Don't slide your components or boards across them. That will build up a static charge on their surface. I also would not disassemble a phone or laptop on one like many sellers say they are good for.
Not have enough money for a proper ESD mat? For many years I soldered on a large cookie sheet I dedicated to that use. My ESD wrist strap was wired to a bolt through the hanging hole. I'd put all my parts onto the cookie sheet while sill in their ESD protective bags, and let them equalize for a few minutes before unwrapping. That is very important. The problem with a metal surface like a cookie sheet is it will drain static at electric shock speed, and that can blow a chip if set down on it without allowing equalizing to happen. This is why the top layer of a 2 layer rubber mat is static disipative, not conductive. Through being careful to always do the equalizing, I never killed a CMOS chip, and this was in the bad old days of the late '70s and early '80s when CMOS chips were much more sensitive to ESD than they are now.
I have since gotten proper two layer rubber ESD mats to cover my cookie sheets. I bought a 2' x 10' roll and cut pieces for them. I think DigiKey has the snap terminals for around $4 each in a screw attachment version. I don't use them. To form a post to attach the ground wire to the mats I use machine screws with nuts clamping fender washers on both top and bottom of the mat. I then use a thumb nut to hold a wire with ring terminal end onto the resulting post. I get as good of electrical contact with them that the snap terminals have, plus they are not likely to accidentally come undone. Also, excluding the thumb nuts, I had all the parts on hand.
The cookie sheets with ESD mats on top are great because I can pick them up and set them onto a shelf relatively quickly without disrupting the laid out parts, tools, instruments, etc on them. My work area is then clear to work on a different project.
My electronics cookie sheets are now all Vollrath #68085 heavy gauge aluminum with mildly turned up ends, and flat along the long edges. It would be better to use stainless steel, but it costs much more. I've thought of making some 24" wide by 18" deep ones (60cm by 45cm) so I have a bit more working room. I'd have to borrow use of a metal break so I can turn up the side and back edges, or have a metal fabricator make them. For the machine screws I used hex socket head machine screws because they are smoother and less likely to damage surfaces they are in contact with. Next time I'd use bevel headed machine screws, and countersink them into the aluminum sheet so they are flush. I also glued 4" wide strips of thick heavy felt to the bottom along the ends to help prevent damage to my tables, and keep fingers from contacting the aluminum which oxidizes over time.
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