I started trading one year ago. I read Jim Cramer book and saved my 10K before investing. Then I invested on companies that I liked based on what I learned. It has been a fun year, what I have learn is that no one can predict the future, but you can almost predict that solid companies will give you “safe” results.
Now, one year later I still have not figured out my selling strategy. I don’t want to fail on the rule “Bulls make money, bears make money, pigs get slaughtered.” Here is my scorecard:

What I read was that once I reached 25% gains I would sell in a systematic approach and that I should not get greedy.
So my questions are:
Is there a reason not to sell a 25% Total Gain?
Does it makes sense to buy the same stock you just sell? I would end up with less quantity of the stock if I do that due to the transactions fee.
If a sell at 25% and buy the same stock. What would “tax wise” happen? For example, if I lost 50% without selling. Do I still have to pay taxes over the 25% already sold?
Buy stocks that I already owned to bring up the average price. Would that be the same as putting money on my worst stocks selection? Even though, it sound mathematically correct it sound that I’m “investing” not for gains but for minimizing my losses.
What advice would you give to me?
Thanks!