Well, I seriously might need more information. How many measures total, and what is actually given (ie, what CAN'T you change) ? And, could you please tell me the registration for whatever pitches are given ?
When you are writing for SATB, you want to consider a few different things. One is voice range for each voice, another is spacing between voices, and then of course you don't want overlapping voices or voice crossing.
Also, I like to start at the end first (because of the need to resolve the tendencty tones) and then the beginning, with the bass line and soprano line first, then filling in the middle. Also, I am not sure what you mean by :
I can't get the V7 to resolve as it should (raise the 3rd and lower the 5th and 7th).
What needs to resolve are the tendency tones within the
scale, found within the V7 chord. So, the 4th scale degree (7th of the chord), resolves DOWN to the 3rd scale degree (also the chordal 3rd in a I chord). The 7th scale degree (the chordal third -- maybe that's what you meant by raising the third ?), Leading Tone, needs to resolve up to tonic. I think it's safer to think in terms of the scale degrees, since you need to make those same resolutions for a vii diminished chord, but they are located differently within the chord structure than within the V7 chord.