A lot of people are asking about the staking process. The "estimate" you are seeing displayed from the wallet should be taken about as seriously as Nostradamus' predictions. If you have a very small number of coins it is possible you will never stake or that it will take an extremely long time (weeks or months) for you to stake. If you want to stake faster, use coin control to combine your coins so they aren't spread out into many chunks attempting to all stake separately. Large chunks = more weight = faster staking.
How is the shown weight calculated? I know only a single transaction can become coinstake, and wallet searches through all eligible transactions while minting. If I have multiple eligible transactions, which weight does it show, total weight?
I believe it should show the weight for whichever chunk of coins in your wallet has the greatest likelihood of staking first.