i have the same problem

Before we even think about ideas for learning words, two things are immediately clear to me: 1) You're probably trying to do more than you can. Pushing many words into your brain is a pretty good way of forgetting most of them. 2) You're not even paying attention properly. Honestly, if you think it's OK to write I as "i" and you as "u", I'm not surprised you have problems. Some of the words in your sentence are not the correct words. It tells me that you didn't learn them properly, and you don't care what your writing looks like. Sorry to sound harsh, but I can see that you're sabotaging your own progress. Take more care with what you already remember, and don't let your own standards drop. Then, think about dealing with more vocabulary.