Rubbish soldering

[gnu]

I'm just in from repairing some electronics in the garage, with the realisation I have become really rubbish at soldering. I struggle now to even tin the wires and the finished job doesn't look too tidy. I used to be okay at it! Could this be related to solders being sold as lead-free now? I noted the solder I used was mainly tin, with a bit of copper and silver alloyed in.

Any tips, like substances to clean the wires and circuit. I used to just strip the wire clean and it worked fine.