If you have modelling magazines there buy them and learn the details.
I built my first models at the age of 11. Glue everywhere and unpainted. I could't afford magazines so learned from my mistakes. 10 years later I was fine detailing cockpits with metal and scratch built plastic and experimenting with dry brushing etc etc. All self taught and I have only ever built 1/72 scale (except for two 1/32 commissions I did).
My advice is buy the cheapest kits you can at first and use them as experiments. Don't expect to make a superb job first time. Hone your skills on them and work up. I used to open the box and study the parts so I knew where they all went and built the kit in my mind. I never committed a piece until I knew it was right. Buy some graph paper so you can align parts against it.
I don't build now due to my eyesight but my top tips are (1) do your homework before you start. Understand the parts and decide in advance which version you are making and that you have the markings correct (2) only ever use as little glue as you can get away with (3) paint should be to scale as well. Imagine you are 1/72 size - what would the paint finish look like? Application is everything and can ruin an otherwise great model. Build up in subtle layers and don't pile it on all at once. Start with brushes and move up to a sprayer later if you want - I only ever used brushes though. (4) never rush a model - Always give each stage time to dry.
And finally don't make the mistake I made many times of starting another model before the last one is finished - it will never get finished!
Good luck and don't forger to post up pics of your work