Best way to play as low level in the city full of enemy?
Solution 1:
You should be able to grind your level up to 2 pretty easily just by hacking enemy portals for 100 AP each time, which is tedious, but past that you're going to have trouble and get bored with 100 AP at a time. Here's a list of things that earn AP - I know most of it is impossible to do at low levels.
You're really not going to be able to do much solo at low levels, so the best option I can think of when you're starting out low level and at a team disadvantage in your area is to organize your local faction and destroy enemy portals in groups. Get at least a couple other people together and attack an enemy portal that is well linked (you'll get more AP for destroying links and fields), low energy and in a location that will allow you to link to the few portals you do control (you get even more AP for creating links and fields than destroying them). It might be hard to find the combo of the those, so take what you can get, but work together.
If you can't find people local at a higher level to help, you might try asking high level players from neighboring towns. Some people are pretty into this game and will take long field trips to help take over outlying regions.
If your opposition isn't very active, you can let your portals decay so that your links and fields disappear, and then relink for a bunch of points.
Finally, a couple options that requires vigilance:
Submit portal suggestions and check to see if they or other portals in your area get added, then be the first to them when they do. You'll need to check http://www.ingress.com/intel and zoom in until it says "Showing all Portals" to be able to see the new portals when they're added.
Another option is to watch your email like a hawk for portal destruction notifications when the enemy destroy a few of your resonators on the few fields you do control, then as with the decaying strategy mentioned before, swoop in and recharge, redeploy and relink your portals. You can do the recharging from a distance if you have the portal key, which will buy you some time to get there to redeploy and relink. I find it helps to leave one low level resonator in an easy to destroy location (like on the sidewalk), and try to place a least one higher level resonator in a hard destroy location (like inside a building). Then you should get notified of the lower level resonator getting destroyed hopefully before they can get to the higher level one.
Solution 2:
What I did- I too started in a highly enemy controlled area. Simply hacking portals is a very slow grind, and not usually worth the gas/time to move around. However I did need to do this at first to stock up on supplies.
Once I had plenty of lvl 1 supplies, I went home and got onto the ingress.com/intel page and zoomed into my area. I zoomed in until it said "showing all portals" and SCOURED the map one screen at a time. This way, I found about 6 portals that nobody had touched. Swoop in, deploy 8 resonators, move on. Also, I paid attention to the intel map, clicking on enemy portals to see the resonator levels. Keep them in mind and check them over several days, and you should be able to find some that nobody is recharging. When a portal was badly decayed (10% energy or less on all resonators) I would swoop in, and start firing off bursters while standing on top of the resonators. Even at lvl 1, the xmp bursts will take out resonators if they are low enough. You may have to use 20 or 30, so make sure you're stocked up.
It's like any other scavenger... Look for the weak and unprotected ones, and go for the kill! Even as a lvl 1 I took out 2 different lvl 4 portals, one percent at a time!
4 days later, I'm lvl 4. War of Attrition.