Okay, since I'm still new to quoting and all this, I'll just have to copy and paste.
"Your subject should start in the 3rd beat of the measure. It's a matter of writing, but quite imortant."
I don't really understand this, can you please explain more? Does this mean having a rest in the first beat isn't a good practice?
"Be careful in your counterpoint, as you're writing many paralel 5ths, 4ths and octaves. In writing in a traditional style, you must avoid the direct movement to perfect consonanses (5th, 4th, 8th, unison)."
I understand the problems with parallel 5ths and octaves, but so far I have not heard of any restrictions regarding parallel 4ths. Also, when you say "avoid direct movement to perfect consonances" what do you mean?
"You start on a high A, then makes the answer a 11th apart. Considering that the A is the III degree of the F#m key, then the answer should be on the III degree of the domiant key (C#m), which is E. You did it well, but an octave lower. It should be on the E of the last upper space. I know it's above the soprano (and you should try to avoid crossing voices for now), but you have a descending subject and descending order of voice-entry. It can be a problem if you don't know how to deal with it well. For now you could: (1) change your subject so that it doesn't end on a note lower than the starting note of the following entry; or (2) change the entry order of the exposition (maybe from bottom to top)."
I read something about the fugue answer being in the dominant, but somehow I could not start the answer on high E above high A, and had to transpose down an octave. I guess I would have to look at more ways to modify the subject.
"Your 3 entries follow a weird order: you start with the soprano (apparently), then goes to the alto but the soprano lowers the register so that it starts to sound like an alto (and the alto like a tenor). Then you have a 3rd entry on the same register of the first one. Which one is the soprano, the 1st or the 3rd?"
I still have much to learn about voicings.
Thanks for your suggestions anyway, I have not actually listened to Bach, and just came up with this to train myself in the use of counterpoint. As to my background, I only had Grade 8 ABRSM music theory knowledge with me, most of all these new things I learnt now I read them online (eg composing fugues). I wonder if there is a book on fugues that I could read about? Most of the books out there are on counterpoint.