I'm not sure why you think picking the losing side is makes it easier to level up. If you pick the winning side, sure when you hack your own portals you don't pick up the measly 100 AP for the hack...but once you get up there in the game a bit....you're going to find you wished you had a lot of ammo. Hacking your own portals often gives 2-4 items. Hacking enemy portals often gives 1 or ZERO items. Couple of tips: When placing resonators, try and do it from as far away from the center of the portal as possible. Once you get past level 1, and have some different resonators to place, stagger them. 2/1/2/1/2/1/2/1 NOT 1/1/1/1/2/2/2/2. This makes it a little harder for the enemy to take out. When attacking a portal, make sure you're standing directly on the first resonator you are going to attack, and attack it until it's destroyed. You should then skip every other resonator.....ie NEWS....then do the NW/NE/SW/SE. It doesn't matter where you start, just keep that pattern. Portals that have the most links and the most control fields attached to it, will have HUGE AP to collect once the portal is destroyed......to the tune of 10-20K depending on how many links/fields are on it (and of course the points you get for capturing the portal, placing all 8 resonators, placing 4 shields, and the 8th resonator is another bonus) Everytime you hack your own portal, hit the link button and see if you can make a link somewhere. Nickel and dime this game to death. Get up early, people aren't going to save their portals at 6AM on a Saturday. I took one out this morning by myself, 20K once all was said and done.
Biggest thing is communicating with your team members, chances are those that have been playing for awhile have a lot of items that they don't really need anymore.....ie level 1 resonators...completely useless once you get past level 3.....unless of course you have an abundance of neutral portals in your area, which is probably unlikely.
Do what you want, but that's just my take on things.