... this year I'll try to talk to girls normally without the intention of impressing them / getting into a relationship with them / sleeping with them...
This is absolutely the way to go. Unless you're a movie star (and even then it's no guarantee) you need to build a certain level of rapport and comfort with somebody before you can take anything further at all. You will get better at this, and you'll find yourself being able to put most girls at ease with your attitude more quickly and more easily in a short time as you do so. One thing that definitely DOESN'T work however is trying to flirt or follow pickup formula without being able to relate. If you load your interactions up with all this pressure to perform with a sexual goal in mind you'll come across at best awkward, at worst, creepy and frightening. In other words, you WILL fail.
Remember this. Boys are largely aroused by looks, Girls are largely aroused by emotions and feelings. I, and I expect you would probably screw the most nasty and socially inept girl in the continent if she was a 10, but girls won't usually do that. You need to learn how to tap into her personality. a great pair of shoes and a big dick might get you an introduction, but if you can't stimulate her heart and mind at least a little, the conversation will end there.
It'll never be 100%, you will get knocked back no matter how confident you might get. Some girls just won't like you or find you attractive, and some girls are just dicks, just like anyone. But you mustn't ever let someone else's opinion or screwed up attitude affect you personally, it's their loss or their problem, not yours. And of course you'll meet some girls that you just won't like too. I doubt you'll lose much sleep over
their anxieties when that happens and you walk the other way.
In the main, girls are just like boys, they don't want to be your therapist or carer, they want to have a laugh, and enjoy themselves. You shouldn't hide the fact that you're a sexual being, that you're a man with desires, but simply being good company goes a long way. Don't focus on yourself, that reeks of insecurity and that's unattractive.
Focus on her and finding out about her. If you show genuine interest in a girl's core character, thoughts and feelings, she'll likely tell you anything you want to know. As to whether she finds you attractive, as TTBB has said, it's a lottery. To a large extent anyway. You can obviously improve your chances but while there are some things that are pretty much universally attractive, there are very few of us that are lucky enough to enjoy trophy status. Even then, whilst those guys might get laid a lot, I expect that's often as unfulfilling as it is for girls when they're seen solely as sex objects.
Ultimately every girl is a bit different, and the only way you'll find out what she's really looking for and what gets her hot under the collar is by
talking to her.
Good luck anyway, I have a feeling you'll be just fine. You're on here trying to improve yourself ain't you? You're already half way there.