a) ... for things that are not to forget (spelling words in other languages, 1x1-in small, data or formulas). Without exercise and without repetition, learning will forget again and soon.
b) ... activities that can not to digest the first time (write beautiful; some gymnastics, singing beautiful thing etc.)
All these could absorb without exercise. If you have a task that must exercise are important following tips and techniques:
Divide your tasks into steps and parts. Do not exercise all at once; piecemeal exercise, one after the other. Example: If you had to learn 35 words (spelling or in a foreign language), divide into five parts (5x7 words). Perform one part after another.
Do not exercise the same thing for too long; make a short break after every quarter of an hour. Better than an hour exercise part are three short exercise periods of 15 to 20 minutes.
English exercised subject must repeat several times during 3-4 days- s! This is crucial, because only thus what carries you, remains steadily in your head. Ideally, the schedule of exercises indicate in your weekly plan, so you do not forget.
Example: Exercise the first two parts in spelling or words in Serbian language ; the first time, for example, today in 2x15 minutes. Monday repeated those words before bedtime. Take the other two parts and reiterated on Tuesday. Exercise during 2 x 15 minutes and repeated before bedtime. Wednesday: Review the parts 1-4; the new 5 Thursday and Friday, all repeated several times.