The best thing to do is always practice. I myself play a majority of Bb instruments just to avoid this problem. "Marking" you music with the lettering is always fine, some students know the letter however, and forget the fingering.... Do not focus on "mastery" but rather accomplishment. I should know-- I have played some horns for nine years and just received vision adequate enough (along with sheet music blown up to 24 size font) to read sheet music. Keep at it!
In treble it is EGBDF and the in the spaces FACE. Bass clef gors GBDFA and ACEG in the spaces. sadly not all music is written in the key of C so you will also need to learn about key signatures. Then after that there is a ton of information about rythms...eight notes, quarter notes and such. For every note there is also a rest that can go in it's place. There are other more obscure clefs after you learn bass and treable that people dont usually think of and then there are tons of notations like fermatas and crescendos and so forth....there's alot to learn.