There are various solutions to this:
Just doing it
.. by which I mean, just tapping the switches and turning the knobs that get you to the setting you need. With practice, you can get quite speedy at this, but at the same time there are practical limitations on what can be achieved.
If this is the only route available to you, you need to plan your pieces so that you don't have unachievable effects changes in a song. Either have changes you can achieve in 1-3 taps, or find space in the arrangement where you can stop playing and attend to your pedals.
Units with multiple effects integrated into one unit. These have programmable patches, selectable by footswitch, that will set all the parameters at once.
Some pedals and rack FX units, can be controlled by MIDI. There are also small businesses that modify non-MIDI pedals to be MIDI controllable. So you can have banks of settings configured in some software, and use a MIDI footswitch to move between them.
Switch between FX chains
Let's say you want to switch immediately from a dirty riffing sound, to a clean reverb-y solo sound. Set up both of those sounds, each using a completely different set of pedals. They could even each go to separate amps, if you like. Connect the guitar to both of these chains through an A/B switch pedal.
Now, at the tap of a footswitch, you can switch from one set of pedals to another.
Obviously this can mean having to own more pedals.
Programmable FX loop systems
This is effectively the solution above, on steroids. Systems such as GigRig route signals through a number of pedals, programmably.
Have someone off-stage (or even on-stage) assist with the FX changes, usually in conjunction with the other techniques. This is what big acts often do. When ZZ Top launch into a solo, Billy Gibbons doesn't step on a stomp-box. An assistant off-stage knows the cue, and switches the effects route at the right moment.