This post is long, but hopefully helpful.
Some players, want and like black trench coat games. These types of players find the challenges of that style very rewarding even when their characters die. As this is the type of game that I tend to run I will try to give you some tips that my players enjoy and I have used to fulfill this play style. They have helped me over the years and may or may not help you.
1. Keep an open dialogue with the players: Ask the players if they truly want this style and if they are alright with character death. During my explanation of this style I tell the players that character death is inevitable in a realistic world and the campaign is not about playing forever but seeing if they can survive to retirement, which is their only other alternative. Many players, I have found like this type of environment. If yours don't then have a discussion and adjust the play environment to suite. Maybe they like more of a black trench coat style but want the ability to pink Mohawk during combat scenes. or they want the game more cinematic. The most important thing is that by talking with the group and keeping the open dialog everyone can find the common ground to have fun.
2. Make yourself accountable: This is a personally belief but I like to hold myself as accountable as possible so I can conduct a fair game. I create rules that I have to follow when conducting counter player actions, like sending in a hit squad and such. These rules are things that I have discussed with the players and in some cases the players have helped me create the rules that eventually got them killed. It was a group effort to create a game that we all have fun playing in. I will go over some of these rules below.
3. Keep a record: If you do do a realistic black trench coat game I find it very helpful to keep a dossier on each player so that when they die or retire, which has only happened once in my games, they have a souvenir of there character. My players enjoy going over a "remember when we did that" session during a dinner or such after a characters death. This dossier is a collection several files that I have made for each entity they have ran against and what those companies know about the character from their after run investigation as well as the amount that the players have cost the company which is used in the rules we use to gauge response, see below.
4. Have fun: if for any reason you or your players are not having fun go back to step one and start a new. the point of playing is that everyone is having fun and to me this is the most important rule. If your players find it fun to have random violence and you want it to be realistic then maybe a barrens game is best. the point is adjust the game to your groups play style not just yours or your players individually.
So you may be curious what rules I use to keep myself accountable the best we can. here are a couple that you can borrow if you like.
1. The response table: Every entity that the runners go against gets a response table made for it and it is the first thing I list in the after action file for that entity in the players dossier. This is kind of like the matrix response table that was in third edition, with levels on it and when players hit different levels the company sends out or hires different assets to locate them and deal with them. All of this is usually hidden from the players but some players have hacked into an entity and taken a look at this file from time to time to see what is in their file. Which I think is a pretty smart move all in all. Typically it is a scale from 1-20, which represents millions of new yen more or less. The actual amount depends on the conversation of realism the players wanted from our open dialogue. A run will typically be a 1-10 damaging run. This is the amount of points that on this scale the players will automatically gain for doing the run and affects their initial payout, 5k plus 2k per (damage level plus teams street cred), this is the top end a Johnson will go but it may not be the starting bid. This is modified by things they do on the run like pay data taken, as this further hurts the company in loss of profit and political backlash usually the amount given to the players divided by 1000 in tenths of a point. So, stealing 2k worth of paydata adds .2 points to the rating. Another modifier we discussed and use is if the players kill a corporate employee, as they now have to pay pension to the widow instead of just being able to punish or fire the employee. I usually add professional rating of each employee killed in tenths of a point to the rating. the rating can go into decimals so a player could have a rating of 5.2 at the end of a run. A player will have a rating on this scale for each job they pull against this entity and they are kept separate until the company connects two of the jobs to the same runner, then the ratings are added together. I'm looking at you distinctive style/leaves a calling card guy. Another rule we added was that a players rating goes down by 1 point per week, so players can actually lay low if they want to ride out a rating. If an old job is reopened due to a connecting factor the full rating is added not the current. For example my players ran against Ares and stole some files they waited out a month and a half to lower their 6 response rating and then went about their merry way. Some time latter they ran against Ares again but they left a clue that they maybe the same team, the mage's astral signature matched the old run. The 6 was immediately added to the response of this run and triggered that a loyalty 3 or less contacts gave up the runners street names and this got added to their file. now later if the same mage is caught running on areas not only is the first runs rating added but also the second. The lesson here is stick to the shadows kids. One more note on the response matrix, they were created by the group before the game started not just by me. the the team finally gets geeked by a professional rating 6 team of runners due to high response, they made the chart that killed them themselves though I have used charts from other games I have ran the players get to see them and modify them during open dialogue first, unless they don't want to see them.
2. Things often don't go according to plan: Before a game session I roll a test with a dice pool equal to the number of missions the players have went on without incident and a threshold of 3, something we set during open dialogue. If I succeed at this test the dice pool is reset for next game but on this one something potentially unforeseen complicates the mission, if I glitch something also goes well for the players. and if I critically glitch... In the Van Goh mission I had one team where it was that one of the fish was quarantined in another location of the building due to a fungus infection. The players didn't find out about it until they got to the fish tank, though they could have if they looked closer into the files in the MET computers. and for another team I critically glitched and they found the security hacker in grossed in an MMO oblivious to what was going on in the node around him, yea he got fired. All in all its a simple rule but it adds a level of unexpectedness to the game and we enjoy it. This is also when the dreck will sometimes hit the fan and identities will sometimes get revealed, but all in all fun.
So, those are a couple of thing I use but onto your post.
New players will quickly become experienced in a game with these types of rules, but remember to start off less strict and work your way back to stricter as they are new and have a learning curve to go through. Though that being said, my players wanted to dive into the deep end and lost over 23 characters in the first year learning the ropes. Most of which happened during the beginning of the year and some due to the complication rule going bad for them but after the first month they became very adept at, sticking to the shadows and they also became better at adapting to changing conditions on the fly. As for the fish tank, my players have learned to gather as much info as they can and that legwork is a must when pulling a job so they knew it was a tank and they knew how much it weighed and so on. They then made a plan using their years of running in this style of game and did the job according to that plan. When the one team got to the tank and realized one of the fish was missing though... ah good times.
