sit-outs, reversals, stand ups, sprawls will all help… toe pressure is key to making you feel heavier… aka get off your knees… (undertones thread disclaimer), chest to chest without letting any other part of your body touch the ground minus the balls of your feet… as for a base, i thought that base was only a wrestling starting position? hand control is key when doing a sit out your elbows should be jammed against your ribs to prevent the opponent from gaining body/wrist control… in fact you should maintain wrist control and as you stand up straighten your arms to break free… atleast thats the idea for wrestling, i never did any other martial arts other than boxing… balance is something that comes with practice, i dont know what to tell you there