Jewelry Store is not that bad to solo (even up to death wish), as long as you can maintain control.
Maintaining control with just one person is tricky without a couple of key skills, though.
- Cable Guy (Aced) - this gives you a total of 6 ties, which is enough to tie the people in the back offices and on the street, which you should do before trying to deal with the inside of the store.
- Control Freak (No Ace Required) - this will let you intimidate people with noise you make - like shooting your unsilenced weapons. It also extends the amount of time they stay intimidated. I tend to take an unsilenced primary to most stealth missions where I plan to control the civs, and then use my secondary silenced pistol on the guards.
With Control Freak, it's pretty trivial to do this even without tying or killing anyone - just keep track of the alerted civs, and shoot some surface near them to keep them under control. The way sound works in Payday 2, you get credit for making a noise when you shoot a gun and wherever the bullet impacts.
I don't know if it's required, but I believe HoxHud will show you icons for where civs are who are about to panic and need to be dominated. It's pretty darn useful for solo'ing, so I suggest using it if you're playing on PC.
So specific strategy for Jewelry Store solo looks like:
Random Event: Did the hot dog stand spawn? If so, there are 2 cops nearby who don't have pagers. If you're playing on a low enough difficulty, it never spawns, but on higher difficulties it sometimes does. You might want to restart the level until it's not there if you're new, but it's doable solo.
Get into the alleyway next to the store, either through the store and out the right office window (carefully) or through the alley on the right side (assuming you can get through there or jump the fence).
Take out any guards in the back alley and side alley, make sure they can't see each other when they go down so you have time to answer pagers.
Get into the right side office (pick the lock on the window if you went through the alley, or just jump back through the window if you went through the store) and wait for the roaming guard to come in the room, shoot him and get his pager.
From here on out, ECMs will keep the whole map safe for however long they last, so use them if the civs are getting out of your control.
(No Control Freak) Make your way back out into the street, and kill or subdue any civs in the street who are away from the front window. Kill the cops at the hot dog stand now, if that's present. I suggest tying until you're out of ties, and then kill anyone else with a silenced weapon. Then walk into the front of the store, and start yelling at people to get down.
(Control Freak) ECM, and walk into the front of the store. Shoot at the walls and ceiling. Make your way out into the street and shoot walls or floor near any civs who aren't green. Do this periodically (every 30 seconds or so) or any time the civs start to get unruly. It only takes a single shot to keep the intimidation going, so don't go crazy or you'll run low/out of ammo. You can shoot outside the map towards civs who are upset, even around corners - it's distance even through walls that counts.
Now, proceed to loot the store, keeping tabs on everybody. Shoot occasionally to keep people down. On Death Wish, you have to drill the safe to get enough bags, so keep that in mind.