Avoid cybercombat (with a caveat).
Cybercombat should be awesome, it should be filled with fantastical icons warping the fabric of cyber-reality, neurons exploding with every attack. Unfortunately it's "Attack, Soak, Counter-attack". I've gotten bored in cybercombat and I'm the team hacker. Cybercombat is also by far the most time intensive thing you can do on the Matrix because it's basically impossible to give a surprise knockout punch, every time I've fought it's turned into a long, dull slugging match.
That's not saying you shouldn't do cybercombat, merely that if you do cybercombat it should be against another hacker, a GOD agent or something similar. Cybercombat betweeen two hackers, each having two agents running Nuke or something is very time consuming but it's actually fun. That's worthwhile every now and then, maybe once every 3 runs. The rest of the time though, cybercombat is just a giant boring time suck.
The easiest way to do this in-game, from my experience, is to have any cybercombat result in an overwhelming response. Get an Active Alert, fight an IC, and the node launches new IC, calls in IC from other nodes, security hackers rush in, etc. Pretty soon you (and your hacker) will be thinking that anytime the hacker gets spotted there's going to be an overwhelming response and so stealth, tricks, etc become the overriding concern. The occasional cybercombat happens when you're hired to whack somebody in cyberspace, you fight the one key guy who runs all the node defenses, etc.
Other than that, I think the rule of four (four die buy one success) is the way to go. For example, if your hacker has a die pool of 12, there's no reason to ever have him roll against an R3 system or lower. There might be some situations where you might want to roll (hacking on the fly against an R3 node with Analyze if the Hacker's stealth isn't great) but for the most part just say "you did it". If the Hacker has a die pool of 16, no roll for R4, at 20 die, no roll against R5.
I actually think just saying "You did it, what's next?" is very important because the other big slowdown is the hacker figuring out which action they're going to take next. In combat you have plenty of downtime between actions for the combatants to figure out what they're going to do next. Hackers don't and the game goes a lot faster if they immediately know what to do next. Saying "You did it, what's next?" gets them to focus on the actions they're taking instead of the dice pools and that speeds up the game alot.
A lot of the actions in the Matrix aren't intuitive so anything that helps the Hacker see exactly how one action leads to another is huge. A lot of the questions people come here with about hacking are "How do I do X?" where X is something simple that requires about five different actions by the hacker. Anything that slows down the flow between one action and the next makes it harder for your hacker to learn how one Matrix action leads to the next. I strongly agree with Incubi that both the GM and the hacker have to know the hacking rules very well, this helps the hacker (and hopefully the GM) become much more familiar with Matrix actions by reinforcing how to use different Matrix actions to do simple real-world things.
As an example, I was recently in a situation where we were infiltrating a prison (yeah, yeah) and the warden wanted to call our "superior" to double check our credentials and I wanted to tap his comcall and reroute it. The guy had a R4 commlink but my hacker runs 16-20 die pools in everything. That can take a long time but there's no real doubt of success. So instead of 5-10 minutes to resolve it, we rolled for hacking on the fly, I knew all the actions to take after that, and we resolved it in under a minute. Felt cool, there was still a bit of risk, and the tension of the situation wasn't lost by a lot of hacking rolls.
Especially if you have a group that's Matrix-wary focus on getting comfortable with the Matrix Actions, then start to worry about dice pools.
Of course, if your group just doesn't want to bother, someone needs to shell out for a decent commlink, a mook (Agent), and some software for it. Should run you about

60,000-

100,000 and nobody has to roll anything, GM handles it separately. Should be about as good as your average script kiddie. It should have a die pool of about 12, so from your perspective it auto hacks R3 links or below, you can make a few secret rolls for R4 systems, and it just fails against R5+ systems. If your team takes this route and wants to hacker tougher systems, somebody better have a high level contact, a lot of nuyen, or both.
Edit:
QUOTE (Udoshi @ Feb 15 2011, 10:32 AM)

A better way to do it is to make the entire PARTY matrix-savvy. They may not be -great- on the matrix, but bringing up situations where they can and should use Augmented Reality to their benefit helps people learn to say, use command, or analyze things so their hacker doesn't have to. Hacking is a minigame; it stops being game derailing when everyone can join.
That would be paradise.