I have some 21 months of investing experience. I have done my fair share of mistakes in this period.
1). Lack of patience, too fast to entry/to fast to exit. (Have saved myself from few deadly falls, but had missed few multi-baggers). Had a tough time getting rid of it. I am yet to control it completely.
2). Investing without doing due research, investing by going through momentum. Haven't burned my fingers because of this, as those stocks are from valuepickr seniors. But because of it, could never develop conviction on ideas.
3). Buying and selling gems like Ajanta multiple time, Had I invested in Ajanta and let it untouched it would have reached 4-8 fold in 2yr time. Have always found reasons to sell (high pe, low delivery volume, etc etc).
4). Inability to have any stock for long term. This is because of 1/2/3. The result, flat 15% tax on all of my profit. The most time I have kept my stock is Astral, that is for just 8 month till now.
5). My inability to get brid of my mental block of investing in high pe stock, even if I know they are not actually costly, and are not likely to quote at any less pe.
These days, I am investing in small number of well researched, well tracked stories, reading ARs of these companies, in a SIP kind of approach. That is taking care of 1, 2, and 4.
As of #3 is concerned, I have no solution, ajanta still looks over-valued to me at cmp, sold 1/3rd of my ajanta holding yesterday prior to bonus announcement.