Well I only up vote the question or answer if
it is very well written, has good detail in few words, to the point and something which is new to me and on this site or exceptional scenario.
Question which seems simple but has a trick behind.
Also the questions which show some next level research. I rarely found these questions types, so my up vote count is very less.
I generally look for mobile side questions here and up vote them without above conditions if it is a real question.
Except I am trying to change this habit as it leads to few up votes. Do I need to improve?
Edit After comments:
It is not always necessary to up vote a question which worth answer, sometimes it happens that I answer a question because i know its solution and don't up vote it because a question with same scenario has been asked previously has little difference but can not be marked duplicate.
Basically I primarily don't think of up vote or down vote I think to help sometimes.
A real question must be answered if we know the best approach to solve it
A good question or answer always have good chances of up vote.
In addition, above mentioned 3 points are strictly followed on StackExchange's StackOverflow site. Fourth is interest dependent.
On Stackexchange, I research on top 9 active technology sites behaviour. Salesforce has good number of up votes per day comparatively (shows good behaviour) and almost no down votes. It is receiving good traffic and standing itself at good position among other site and youngest among all competitors (However Magento site may win). Salesforce is not the top but has 25th rank.
Instead of complaining up votes we should motivate Questioners to accept the answer if it solved their problem. SalesforceStack is significantly behind in this case. It has low answer acceptance rate even several questions have good and perfect answers. They remain up voted only.
One of the fact is that few don't up vote answers/questions if they don't like our question/answer according to their patterns of answering/questioning. E.g; This answers has a down vote because this voting pattern is wrong according to them or may be for more users.