trouble with fm transmitter

i made an fm transmitter, 1 of the 2 transistor types.it worked fine on a bread board but when i put it on to strip board it became very unstable (frequency drift n all that lark).
some things to note are:

i didnt cut the leads after soldering coz i wanted to be able to salvage the parts if it didnt work
2 wires placed slightly apart worked better than the trimmer capacitor

if i cut the leads will this solve the instability?

Thoughts, based on wisdom passed along to me by people I'd regard as experts.

1. Keep all leads short.
2. Mechanical stability is important. If you can see it move it's moving too much.
3. All unused copper on the board should be ground - and there should be lots of copper connected to ground.
4. A good enclosure is important - reduces impact of energy sources and objects nearby.
5. Power supply voltages must be stable.
6. Conductors that are near each other will exhibit inductance and capacitance. A 'gimmick' capacitor is simply two wires twisted together. All they need to do is be near each other at that frequency.

Not sure how much you should expect from a simple circuit. It would seem that the oscillator would be easy to affect. Anything that gets near the antenna will probably influence the oscillator. Temperature is likely to have an effect as well.