First thing is to remove all the negative things in your mind
Whenever a person starts his workout be it running , kickboxing,weight lifting , (HIT) high intense training. First thing that hits your MIND is, will i be able to run so far ? will i be able to kick that high ? will i be able to lift such heavy weight ? can i match his fitness levels ?can i do 400 push ups in an hour ? all these negative thoughts put you down,and you always end up doing your normal routine and find no results.
End the negative thoughts and convert them into positive thoughts, say for example if your kickboxing routine has 100 punches and 50 push ups in each set, instead of thinking this is going to be tough and my shoulders and triceps will hurt very badly change your thoughts to this 100 punches and 50 push ups might look tough but this is going to make my punch stronger and quicker where i can take down my competitor easily in the ring and all that push ups what i do will give me all the strength to take those blows from my opponent easily.
when you start your routine redefine yourself. You might have thoughts like “i will always be fat” , “i could never do push ups i don’t think i will be able to do it” when people see their physical short-come they have negative thoughts and these negative thoughts will always make a person a failure or loser in life.
start redefining , be the person where you get only what you put in. And once you shape up your mind in this manner you will have improvements
Be mentally prepared and make sure this becomes your habbit and automatically you will find results.