What can someone thinking about changing fields after PhD do in practice in order to improve his changes for getting his first postdoc and being a successful researcher? Some have suggested going to conferences in the new field and making connections during the PhD, but it seems quite impossible to have the time for that because there still is a thesis to finish and limited funding for conferences. Also, if there is a wider area of interesting new fields, that seems quite limiting: postdoc positions are rare, after all, and it would be beneficial to be a good fit for many open positions, so one connection in one particular field might not be the best option. What other things can be done?
In addition, and perhaps most importantly, jumping from field to field doesn't seem promising for getting a permanent position somewhere because the time needed to learn new tricks is obviously time away from doing good research. So, should one have a long term "plan" in this phase at the latest?