Most android games are crap, and even worst, most of the games have no demo's, and the few that have demos, provide such a limited experience that it makes the game look bad.
free to play, if done right, can be very profitable, but if you are greedy with it and go crazy with pushing micro transactions, then people will leave you in droves.
Most free to play mobile games are set up in a way where you are punished for not paying, or if it is multiplayer then you are in a situation where someone who has paid for a few extra items has an unfair advantage.
DRM is not the way to stop piracy, the way to stop it, is to offer something that the pirates cant offer, and that is features that increases the ease of use. (for example, steam games have less piracy even though they are easier to crack, and that is because of the convenience of how steam manages the games, and even saves disk space by consolidating files that are used in between games).
At my work place, I helped set up a firewall (that was very expensive to handle all of the users and has a monthly fee that is not exactly small business friendly. but they wanted it because when I find a issue with the firewall, I can simply call someone up or e-mail them, and I will be taken seriously and in a few days, I will have a update sent out that fixes the issue.
If you are a developer and are charging people for your software, then you have to have the right mindset for providing customer service. If someone is having an error message when downloading the game content and they contact you for support and your first response is to accuse them of piracy, then when they provide proof of purchase, you then offer no help and never get back to the person on your efforts to research the issue and fix it, then what do you expect.
if you want to sell games, then provide a good way for people to sample the game, let them play like 1/4th or 1/3rd of the game with no limitations compared to the full paid copy.
if it is a MMO then let them play the same as a paid copy until a certain level.
(if people can put the effort to go through a large portion of the game then they pretty much want to see the whole thing through)
A demo should allow a user to demo the full experience of a game. Stop releasing crippled ones as idiots like the complaining developers that do it, poison the well for demoing software, and thus more people are likely to pirate the game, and thus more likely to forget to pay for it if they really like the game..
Also be ready to offer good customer service. (I am not saying it is easy, but it is a must). A dev team that supports the customers will attract more customers. if someone has an issue and contacts you about it, providing s**t service (eg a generic response and never getting back to them, or accusing them of pirating until they can prove that the copy is paid for, or any other thing that does not involve acknowledging the issue and responding with a solution, or offering a blog post update if many are having the issue, and if no solution is available, then being proactive with updates on fixing the issue, then don't complain when people fail to see the value in paying for the software.
For me, I don't really game, I only played one game on android (free copy of angry birds which kinda sucked) there are just no good indepth games like you would find on the PSP, or nintendo DS or other portable consoles, and while they are not priced as such, for those portable consoles, those good indepth games eventually become just as cheap when they hit the bargain bin but offer many times more value.
also don't expect some 2D game that becomes repetitive after a few minutes to sell as well as a game such as elder scrolls skyrim, and don't blame it on piracy when you don't hit your goal of 500000 billion sales or some other unrealistic expectation for your buggy game that you want people to pay for and have faith that you will someday release a patch.