1. Give assigned experience points to buy wealth, reputation, and contacts - or give bonuses to contact relationships - for people who role play it well. In other words, all those "background perks" develop with roleplaying, not just expenditures. Players will generally jump on board if they think they can get a freebie. And remember that those contacts are two way streets. Anyone the player has a contact probably has the player as a contact - so let the contact call up and ask for help. For example, I'm running in a comined Marvel/DC world. One of the characters had Spidey as a contact. As a plot hook recently, I had Spidey call up and ask for help with Carnage. Since the PC group came running right away, I gave the player +1 to his relationship with Spidey when the night was over. Reputation perk is another good place to give freebies. If they roleplay it well, maybe give them +1 to their wealth.
Perks can be very useful, but also very easy to control.
2. Suggest putting points into a group base or vehicle(or improving the current one). For 8 or 10 points each, the group can have a vehicle which is much faster than any of the chracters and can get them all there at the same time. You can buy a VERY basic base for 18 or 20 points total, but X-Men style danger rooms and Avengers level security can get very expensive, very quickly.
3. Don't forget that villains get experience too. Everytime you use a villain, give them a few points at the end of the night to buy a couple more DEF, another MP slot, or an extra die on their EB. Just make sure to keep it balanced. And you can always give them a tougher class of villains. After all, you've got stats for Dr. Destroyer, Firewing, and the like. So maybe it's time to use them.
4. Another thing I try to do in my campaigns is use a "paper trail" which is twofold. First, we have a "newspaper" of sorts which details not just the PC's latest adventure(if it was public enough and noteworthy enough) but also details what other heroes/villains were doing(handy excuse for a contact not being around even if the character makes the roll) and can be used to introduce plot hooks for adventures(a spate of robberies, etc). The other is what we initially called "bluebooks"(because we used college exam "bluebooks" until they became too expensive, now we use cheap folders with notebook paper). At the end of each night, or between adventures, the players write down what their characters are doing "between sessions" this gives the player a chance to develop a contact, improve their business, etc without it taking time away from the main session with the other players...and can be a good place to start adventures involving the character's personal life(their store gets robbed, someone infilitrates their company, a hunted kidnaps a DNPC, you've got all kinds of possibilities here).
Last night's M&M game. The heroes arrive at the scene of a tech theft just in time to catch the thieves exiting the building through a hole they've blasted in the sixth floor. A man is thrown from the hole; Solar Core catches him in mid-air and returns him safely to the ground. His name is Dr. Clarence Clearwater.
"Clarence Clearwater... is he unconscious?"
"Wake him up. It'll be a Clarence Clearwater Revival!"