Very little carbonation

[g-pa]

am new to extract brewing I am starting my 4th batch (liberty cream ale) my first two were irish red and the 3rd was honey weizen ( all extract) they all tasted fairly well , the irish reds had little carbonation and the honey weizen had VERY little all were 1 week in primary , 2 in secondary and three in the bottle at 68-70 deg. I primed with 3/4 cup corn sugar boiled with 1 cup water and mixed well . The bottles were on a table(not the floor) , the same place as the primary and secondary fermentation it seemed to be fermenting very well there @ 68 -70 deg

and the carbonation.it does have, does not last long at all. and I cleaned the glasses and rinsed

any suggestions as to what am might be doing wrong? I thought about using muntons carb drops but dont know if that will help me any

[slothrob]

and the carbonation.it does have, does not last long at all. and I cleaned the glasses and rinsed

Does your beer not have much carbonation (3/4 cup should be more than enough priming sugar) or not much head?

They are connected but have different possible solutions.