To answer that question you first have to ask yourself what is the outcome you are seeking.
I think most people on here are mainly trying to control for their risk and want a modest profit with hopefully a modest downside risk. So the methods are to only increase the sizing once you already have some profit from an initial pilot position. The size of the second parcel should still be modest so that the average cost remains below the current trading price. If the trend continues you can gradually increase the size of the following parcels and maintain a stop loss which is close to your breakeven position.
On the other hand if you are out to break the casino (and can tolerate high volatility and big drawdowns on failure) you spend a lot of time waiting until you see something you really like... then buy early and buy big. I am this sort, but I still actively try to control for the risk.
I will take an initial position and buy more if the price moves either way (up or down) but once I have bought 3 or 4 parcels I will trade some percentage (if in profit) to try to work the average price down. The sorts of things I get into are speculative and so the uncertainty creates a lot of volatility. As an example... I am doing well with IPT and have been in it for nearly 3 years. Over that time I traded the price from 0.008 up to 0.018 then down to 0.012 and up to 0.024 ending up with a useful free carry in a company still in early stage growth. The same strategy with CAI has led to grief (so far... haven't given up yet and still believe in the company). I tend to concentrate on 1 or 2 companies at a time. Currently I have a big position in RNX which will either set me back on my arse or allow me to make bigger bets on a few other things I like.
Your own psychology plays the largest part. I think you have to act in accordance with that. When you say that you used to be disciplined in your strategy but now can be random in how you play... it makes me think you have succumbed to frustration. If so that is a slippery slope which ends badly. Never underestimate the power of doing nothing! When you lose sight of how to proceed it is a good time to rest and reassess. Work out exactly what your goals are and what feels best for you in how to achieve them.
