I think I've been too addicted to the web app.. upto 32k coins now and still trying to sell Kabir for 20k... at this rate I'll crack the 100k in a weeks time

..
Dunno the best way to go about making a team though... I've always liked Doumbia, Wellinton and McGready so they're all in the Russian league together but other than that not sure what to do..
I've run the battery on my phone dead multiple times messing with the web app on it.
Some sites that I use constantly (you probably know these)
ultimatedb.nl (player/consumable prices)
futhead.com (squad building... invaluable)
Basically play with Futhead as much as you can, try different players in different formations/combinations etc and you'll get an idea of how chemistry works. That's the best way to build teams, once you get the idea down re: chemistry you can build all sorts of crazy hybrid teams.
I did an experiment a couple of months back to see how much I could make in a week starting from a single 400 coin bronze pack and just doing some basic trading (buy player for 1000, sell for 1500 etc) for 30 minutes to an hour per day and I wound up with 240k by the end of the week. If you can find 2-3 really popular players that sell for around 800-1.1k coins at their cheapest you can make a fortune quickly.
I'm not trading anymore because I got bored with it but the ones I targeted were Agbonlahor and Sturridge, also Darren Bent but only in good formations. You could get them from roughly 800-1.1k and I'd sell them for 1.5k each and clear my trade pile multiple times per day. 30 slots on the trade pile at 500 coin profit per slot makes 15k, clear your trade pile 4-5 times a day and you're making 75k per day in profit roughly