Ill break down how I juice up my Liberals, it might help explain some stuff.
Take a squad of goons, lets say we want to make some musicians, so having no rap sheets are important. I recruit a squad of 5 or 6, whatever you want.
Step 1. set them all to liberal disobedience, they will improve to 20 juice, occasionally 23 for some reason. There is a risk of your liberals getting caught and getting a) badly beaten, b) arrested something very low order, I cant remember what its called, c) both. the risk isnt high but doing community service is a no danger way to get to 10 juice if you want to take that option.
Step 2. dump them all in a squad and equip someone with a spraycan, then send the squad to the crackden or whatever. Spray away until everybody has 50 juice. As stated by other people you dont get criminal charges from crimes commited onsite, only while escaping from the crackden/slum/etc.
step 3. I send whoever I want to be trained up further to a squad that lives in one of the upmarket apartments, the squad is led by my founder or a prostitute I have trained up. Both have good lockpick, seduction, disguise, persuasion, charisma and driving. The trick with this is that stealing from rooms doesnt seem to cause any charges, it is breaking down doors that give the charges if you can get away ok. So use the map, look for decent amounts of loot on the lower 2 floors and then get out. Dont break down any doors, dress everybody up in police uniforms to make things a bit easier. If you meet a low level conservative in a room, try for a seduction (makes the conservative dissapear), if it is high level just run away. Use your pro team leader to bluff past anybody who you meet on the way out, this is good for 10-80 juice a day. As long as you stay in the lower 2 levels and dont stuff about getting out if the alarm is raised its not a hard grind to get to 200 juice.
I usually think that 200 juice is fine for my 'base level' operatives. taggers, drug runners, musos, hackers etc.
I have 3 problems with having my musos go and bash teenies in the crack den 1. my hippies are generally fat and lazy, I picked then for their 15 starting heart, not their agility, so they cant run if you hang about too long, I got sick of losing whole squads after sticking around too long. 2. A squad of 6 doesnt get that much juice from a bashing, only the hitter gets juice each time, and the teenie can go down after 2 rounds. 3. conservatives get a bit sparse on the ground in the crack dens after you kill a few, I always got inpatient and got a few of my guys shot by gangmembers or bikers or something.
edit: well the community service doesnt gain juice anymore so that is out. Stealing still isnt a crime if you dont get caught though.